[quiche] Fix deps/public_deps

The recent quiche upgrade refactored "octets" into a separate
crate, but it's not a public dependency.

Change-Id: I97cc2660186e42ecc135f05ec2d8112d8c383223
diff --git a/BUILD.gn b/BUILD.gn
index 81f9134..75919c6 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -5,6 +5,8 @@
 group("quiche") {
     public_deps = [
         "quiche:quiche",
+    ]
+    deps = [
         "octets:octets",
     ]
 }