Prepare Webdev for release to 3.0.8 (#2224)

Author: elliette

test_common/pubspec_overrides.yaml renamed to test_common/ignore_pubspec_overrides.yaml

@@ -1,6 +1,7 @@
-## 3.0.8-wip
+## 3.0.8
 
 - Update Dart SDK constraint to `>=3.2.0-36.0.dev <4.0.0`. - [#2207](https://github.com/dart-lang/webdev/pull/2207)
+- Update `dwds` constraint to `21.0.0`.
 
 ## 3.0.7
 

webdev/CHANGELOG.md

@@ -1,6 +1,6 @@
 name: webdev
 # Every time this changes you need to run `dart run build_runner build`.
-version: 3.0.8-wip
+version: 3.0.8
 # We should not depend on a dev SDK before publishing.
 # publish_to: none
 description: >-
@@ -19,7 +19,7 @@ dependencies:
   crypto: ^3.0.2
   dds: ^2.2.0
   # Pin DWDS to avoid dependency conflicts with vm_service:
-  dwds: 20.0.1
+  dwds: 21.0.0
   http: ^0.13.4
   http_multi_server: ^3.2.0
   io: ^1.0.3