Remove `release` tag for build job

The variables are now defined inside of Settings > CI/CD > Variables and we no longer need a specific Runner.

Job running on private/shared runner fleet: https://gitlab.com/gitlab-org/ci-cd/gitlab-runner-ubi-images/-/jobs/483037833 Job running on release runner: https://gitlab.com/gitlab-org/ci-cd/gitlab-runner-ubi-images/-/jobs/482623455

reference gitlab-org/gitlab-runner#21299 (closed)