Bump google-protobuf from 4.28.1 to 4.28.2 in /docs

Bumps [google-protobuf](https://github.com/protocolbuffers/protobuf) from 4.28.1 to 4.28.2.
- [Release notes](https://github.com/protocolbuffers/protobuf/releases)
- [Changelog](https://github.com/protocolbuffers/protobuf/blob/main/protobuf_release.bzl)
- [Commits](https://github.com/protocolbuffers/protobuf/commits)

---
updated-dependencies:
- dependency-name: google-protobuf
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <support@github.com>

docs/Gemfile.lock

@@ -28,13 +28,13 @@ GEM
     font-awesome-sass (6.5.2)
       sassc (~> 2.0)
     forwardable-extended (2.6.0)
-    google-protobuf (4.28.1)
+    google-protobuf (4.28.2)
       bigdecimal
       rake (>= 13)
-    google-protobuf (4.28.1-arm64-darwin)
+    google-protobuf (4.28.2-arm64-darwin)
       bigdecimal
       rake (>= 13)
-    google-protobuf (4.28.1-x86_64-linux)
+    google-protobuf (4.28.2-x86_64-linux)
       bigdecimal
       rake (>= 13)
     http_parser.rb (0.8.0)