Bump google.golang.org/protobuf from 1.30.0 to 1.33.0 in /docsgen

Bumps google.golang.org/protobuf from 1.30.0 to 1.33.0.

---
updated-dependencies:
- dependency-name: google.golang.org/protobuf
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

Diff for: docsgen/go.mod

@@ -96,7 +96,7 @@ require (
 	golang.org/x/tools v0.6.0 // indirect
 	google.golang.org/genproto v0.0.0-20230410155749-daa745c078e1 // indirect
 	google.golang.org/grpc v1.56.3 // indirect
-	google.golang.org/protobuf v1.30.0 // indirect
+	google.golang.org/protobuf v1.33.0 // indirect
 	gopkg.in/ini.v1 v1.66.2 // indirect
 	gopkg.in/src-d/go-billy.v4 v4.3.2 // indirect
 	gopkg.in/src-d/go-git.v4 v4.13.1 // indirect