[Chore][CI] Limit release-image-build workflow to only take tag as input #3016
Description
Use #3015 as a reference, make https://github.com/ray-project/kuberay/blob/f6bf32ff83cfbcdab9405b443322d43cbe075393/.github/workflows/image-release.yaml also take only tag as input and completely removes all inputs from workflow_dispatch.