bzlmod: Add support for `go_proto_library` (#3283)

This does not include support for `go_grpc_library` yet.

Fixes #3265
diff --git a/MODULE.bazel b/MODULE.bazel
index 723601e..5bae3e8 100644
--- a/MODULE.bazel
+++ b/MODULE.bazel
@@ -12,6 +12,8 @@
 
 bazel_dep(name = "bazel_skylib", version = "1.2.0")
 bazel_dep(name = "platforms", version = "0.0.4")
+bazel_dep(name = "rules_proto", version = "4.0.0")
+bazel_dep(name = "protobuf", version = "3.19.2", repo_name = "com_google_protobuf")
 
 non_module_dependencies = use_extension("//go/private:extensions.bzl", "non_module_dependencies")
 use_repo(
@@ -25,5 +27,9 @@
 
 bazel_dep(name = "gazelle", version = "0.26.0")
 go_deps = use_extension("@gazelle//:extensions.bzl", "go_deps")
-go_deps.module(path = "github.com/golang/mock", version = "v1.6.0", sum = "h1:ErTB+efbowRARo13NNdxyJji2egdxLGQhRaY+DUumQc=")
-use_repo(go_deps, "com_github_golang_mock")
+go_deps.from_file(go_mod = "//:go.mod")
+use_repo(go_deps,
+    "com_github_golang_mock",
+    "com_github_golang_protobuf",
+    "org_golang_google_protobuf",
+)
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..663b390
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,9 @@
+module github.com/bazelbuild/rules_go
+
+go 1.18
+
+require (
+	github.com/golang/mock v1.6.0
+	github.com/golang/protobuf v1.5.2
+	google.golang.org/protobuf v1.28.0
+)
diff --git a/go.sum b/go.sum
new file mode 100644
index 0000000..fda83a9
--- /dev/null
+++ b/go.sum
@@ -0,0 +1,34 @@
+github.com/golang/mock v1.6.0 h1:ErTB+efbowRARo13NNdxyJji2egdxLGQhRaY+DUumQc=
+github.com/golang/mock v1.6.0/go.mod h1:p6yTPP+5HYm5mzsMV8JkE6ZKdX+/wYM6Hr+LicevLPs=
+github.com/golang/protobuf v1.5.0/go.mod h1:FsONVRAS9T7sI+LIUmWTfcYkHO4aIWwzhcaSAoJOfIk=
+github.com/golang/protobuf v1.5.2 h1:ROPKBNFfQgOUMifHyP+KYbvpjbdoFNs+aK7DXlji0Tw=
+github.com/golang/protobuf v1.5.2/go.mod h1:XVQd3VNwM+JqD3oG2Ue2ip4fOMUkwXdXDdiuN0vRsmY=
+github.com/google/go-cmp v0.5.5/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
+github.com/yuin/goldmark v1.3.5/go.mod h1:mwnBkeHKe2W/ZEtQ+71ViKU8L12m81fl3OWwC1Zlc8k=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
+golang.org/x/mod v0.4.2/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
+golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
+golang.org/x/net v0.0.0-20210405180319-a5a99cb37ef4/go.mod h1:p54w0d4576C0XHj96bSt6lcn1PtDYWL6XObtHCRCNQM=
+golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.0.0-20210220032951-036812b2e83c/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20210330210617-4fbd30eecc44/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20210510120138-977fb7262007/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
+golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
+golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
+golang.org/x/tools v0.1.1/go.mod h1:o0xws9oXOQQZyjljx8fwUC0k7L1pTE6eaCbjGeHmOkk=
+golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+google.golang.org/protobuf v1.26.0-rc.1/go.mod h1:jlhhOSvTdKEhbULTjvd4ARK9grFBp09yW+WbY/TyQbw=
+google.golang.org/protobuf v1.26.0/go.mod h1:9q0QmTI4eRPtz6boOQmLYwt+qCgq0jsYwAQnmE0givc=
+google.golang.org/protobuf v1.28.0 h1:w43yiav+6bVFTBQFZX0r7ipe9JQ1QsbMgHwbBziscLw=
+google.golang.org/protobuf v1.28.0/go.mod h1:HV8QOd/L58Z+nl8r43ehVNZIU/HEI6OcFqwMG9pJV4I=
diff --git a/tests/bcr/MODULE.bazel b/tests/bcr/MODULE.bazel
index 8c4b535..374cda5 100644
--- a/tests/bcr/MODULE.bazel
+++ b/tests/bcr/MODULE.bazel
@@ -8,6 +8,7 @@
     module_name = "rules_go",
     path = "../..",
 )
+bazel_dep(name = "protobuf", version = "3.19.2")
 
 # Test that this correctly downloads the SDK by requesting it from the commandline (see presubmit.yml).
 go_sdk = use_extension("@my_rules_go//go:extensions.bzl", "go_sdk")
diff --git a/tests/bcr/proto/BUILD.bazel b/tests/bcr/proto/BUILD.bazel
new file mode 100644
index 0000000..c53c972
--- /dev/null
+++ b/tests/bcr/proto/BUILD.bazel
@@ -0,0 +1,24 @@
+load("@my_rules_go//go:def.bzl", "go_test")
+load("@my_rules_go//proto:def.bzl", "go_grpc_library", "go_proto_library")
+
+proto_library(
+    name = "foo_proto",
+    srcs = ["foo.proto"],
+    deps = [
+        "@protobuf//:empty_proto",
+    ],
+)
+
+go_proto_library(
+    name = "foo_go_proto",
+    importpath = "example.com/foo_proto",
+    proto = ":foo_proto",
+)
+
+go_test(
+    name = "foo_test",
+    srcs = ["foo_test.go"],
+    deps = [
+        ":foo_go_proto",
+    ],
+)
diff --git a/tests/bcr/proto/foo.proto b/tests/bcr/proto/foo.proto
new file mode 100644
index 0000000..26a8097
--- /dev/null
+++ b/tests/bcr/proto/foo.proto
@@ -0,0 +1,11 @@
+syntax = "proto3";
+
+package tests.bcr.proto;
+option go_package = "example.com/foo_proto";
+
+import "google/protobuf/empty.proto";
+
+message Foo {
+  int64 value = 1;
+  google.protobuf.Empty empty = 2;
+}
diff --git a/tests/bcr/proto/foo_test.go b/tests/bcr/proto/foo_test.go
new file mode 100644
index 0000000..ff3f475
--- /dev/null
+++ b/tests/bcr/proto/foo_test.go
@@ -0,0 +1,16 @@
+package proto_test
+
+import (
+	"testing"
+
+	"example.com/foo_proto"
+)
+
+func TestFoo(t *testing.T) {
+	msg := &foo_proto.Foo{
+		Value: 1,
+	}
+	if msg.Value != 1 {
+		t.Fail()
+	}
+}