Move version updation logic to release-tools
For ominbus-gitlab, the logic which bumps
*VERSION files is done in release-tools as part of release. We are doing the same thing for CNG in gitlab-org/release-tools!551 (merged). The advantage of this is the files will already be available in the FS, and we need not "fetch them" from a URL. This makes it easier for security releases, which require fetching from dev, which requires using API.