Add subdirectory prefixed tags to release process to support Go SDK versioning.

BEAM-5379 updated the SDK to use modules for Dependency management for 2.33.0 but it isn't behaving as expected. The release versions are being ignored.

Turns out we misunderstood one facet of having the go.mod file not at the root directory: to version that package, version tags must be prefixed with the directory path to the go.mod file.

See https://golang.org/ref/mod#vcs-version for the description.

We've validated that adding such a prefixed tag to a release branch resolves the issue.
https://pkg.go.dev/github.com/apache/beam/sdks/v2@v2.34.0-RC1/go/pkg/beam?tab=versions

This JIRA is to track adding the version tags to the release processes so we can continue paired releases for all SDKs, and back updating 2.33.0 with a tag so we can keep it as the first "non-experimental" release.

Further discussion:
https://lists.apache.org/thread.html/r987ea3540a0457ede258a96a0748b9af39c1de0acd83e822de8d0abb%40%3Cdev.beam.apache.org%3E