Preparing release v1.3.0 (#30)

This releases v1.3.0 of multierr with support for Go modules.
diff --git a/CHANGELOG.md b/CHANGELOG.md
index f1b852c..f0055f8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,12 @@
 Releases
 ========
 
+v1.3.0 (2019-10-29)
+===================
+
+-   Switch to Go modules.
+
+
 v1.2.0 (2019-09-26)
 ===================
 
diff --git a/go.mod b/go.mod
index a500396..5463fac 100644
--- a/go.mod
+++ b/go.mod
@@ -3,11 +3,10 @@
 go 1.12
 
 require (
-	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/stretchr/testify v1.3.0
-	go.uber.org/atomic v1.4.0
+	go.uber.org/atomic v1.5.0
 	go.uber.org/tools v0.0.0-20190618225709-2cfd321de3ee
 	golang.org/x/lint v0.0.0-20190930215403-16217165b5de
-	golang.org/x/tools v0.0.0-20191029041327-9cc4af7d6b2c // indirect
+	golang.org/x/tools v0.0.0-20191029190741-b9c20aec41a5 // indirect
 	honnef.co/go/tools v0.0.1-2019.2.3
 )
diff --git a/go.sum b/go.sum
index 174cd00..b460913 100644
--- a/go.sum
+++ b/go.sum
@@ -15,8 +15,8 @@
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.3.0 h1:TivCn/peBQ7UY8ooIcPgZFpTNSz0Q2U6UrFlUfqbe0Q=
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
-go.uber.org/atomic v1.4.0 h1:cxzIVoETapQEqDhQu3QfnvXAV4AlzcvUCxkVUFw3+EU=
-go.uber.org/atomic v1.4.0/go.mod h1:gD2HeocX3+yG+ygLZcrzQJaqmWj9AIm7n08wl/qW/PE=
+go.uber.org/atomic v1.5.0 h1:OI5t8sDa1Or+q8AeE+yKeB/SDYioSHAgcVljj9JIETY=
+go.uber.org/atomic v1.5.0/go.mod h1:sABNBOSYdrvTF6hTgEIbc7YasKWGhgEQZyfxyTvoXHQ=
 go.uber.org/tools v0.0.0-20190618225709-2cfd321de3ee h1:0mgffUl7nfd+FpvXMVz4IDEaUSmT1ysygQC7qYo7sG4=
 go.uber.org/tools v0.0.0-20190618225709-2cfd321de3ee/go.mod h1:vJERXedbb3MVM5f9Ejo0C68/HhF8uaILCdgjnY+goOA=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
@@ -36,6 +36,8 @@
 golang.org/x/tools v0.0.0-20190621195816-6e04913cbbac/go.mod h1:/rFqwRUd4F7ZHNgwSSTFct+R/Kf4OFW1sUzUTQQTgfc=
 golang.org/x/tools v0.0.0-20191029041327-9cc4af7d6b2c h1:IGkKhmfzcztjm6gYkykvu/NiS8kaqbCWAEWWAyf8J5U=
 golang.org/x/tools v0.0.0-20191029041327-9cc4af7d6b2c/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
+golang.org/x/tools v0.0.0-20191029190741-b9c20aec41a5 h1:hKsoRgsbwY1NafxrwTs+k64bikrLBkAgPir1TNCj3Zs=
+golang.org/x/tools v0.0.0-20191029190741-b9c20aec41a5/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/errgo.v2 v2.1.0/go.mod h1:hNsd1EY+bozCKY1Ytp96fpM3vjJbqLJn88ws8XvfDNI=