Add visibility of plugin.proto to python directory
diff --git a/src/google/protobuf/compiler/BUILD.bazel b/src/google/protobuf/compiler/BUILD.bazel
index cfbf714..a0f3e84 100644
--- a/src/google/protobuf/compiler/BUILD.bazel
+++ b/src/google/protobuf/compiler/BUILD.bazel
@@ -207,7 +207,10 @@
 
 exports_files(
     srcs = ["plugin.proto"],
-    visibility = ["//:__pkg__"],
+    visibility = [
+        "//:__pkg__",
+        "//python:__pkg__",
+    ],
 )
 
 cc_library(