Upgrade goLang protobuf version

[qcdyx]

The latest stable version of the recommended Go Protobuf module, google.golang.org/protobuf, is v1.36.11 as of December 12, 2025.
We should upgrade to this version to ensure we have the latest security fixes, performance improvements, and compatibility.

• Update golang/gtfs/go.mod to require google.golang.org/protobuf v1.36.11.
• Run go mod tidy in golang/gtfs/ to update go.sum.
• Check if protoc-gen-go in golang/Dockerfile needs an update to match the runtime (currently v1.28.1).
• Re-run the build and tests using the Docker container.
• Use Example code to test the new bindings