Prepare to publish protobuf 4.0.0 and protoc_plugin 22.0.0 (#969)

Author: mraleph

protobuf/CHANGELOG.md

@@ -1,4 +1,4 @@
-## 4.0.0-wip
+## 4.0.0
 
 * **Breaking:** The following types and members are now removed:
 

protobuf/pubspec.yaml

@@ -1,5 +1,5 @@
 name: protobuf
-version: 4.0.0-wip
+version: 4.0.0
 description: >-
   Runtime library for protocol buffers support. Use with package:protoc_plugin
   to generate Dart code for your '.proto' files.

protoc_plugin/CHANGELOG.md

@@ -1,4 +1,4 @@
-## 22.0.0-wip
+## 22.0.0
 
 * Remove `PbEventMixin` mixin. ([#738])
 * Type of repeated fields is now `PbList` (instead of `List`), type of map
@@ -30,7 +30,7 @@
 [#935]: https://github.com/google/protobuf.dart/pull/935
 [#955]: https://github.com/google/protobuf.dart/pull/955
 [#963]: https://github.com/google/protobuf.dart/issues/963
-[#153]: https://github.com/google/protobuf.dart/issues/153
+[#159]: https://github.com/google/protobuf.dart/issues/159
 
 ## 21.1.2
 

protoc_plugin/pubspec.yaml

@@ -1,5 +1,5 @@
 name: protoc_plugin
-version: 22.0.0-wip
+version: 22.0.0
 description: A protobuf protoc compiler plugin used to generate Dart code.
 repository: https://github.com/google/protobuf.dart/tree/master/protoc_plugin