feat: pass GIT_SHA/GIT_BRANCH/VERSION build args to docker build (#390)

Forwards `GIT_SHA`, `GIT_BRANCH` and `VERSION` to the docker build in
the deploy action. `GIT_SHA` is the full commit that's already computed
for `COMMIT_HASH`, `GIT_BRANCH` is the source ref, and `VERSION` is the
source ref plus the short commit (e.g. `main-626c2f2`).

We changed the ethrex Dockerfile and it now reads these build args to
stamp the version into the image. Without them the ethpandaops/ethrex
images report an unknown version/commit and the OCI revision/version
labels come out empty.

The values are already on hand here, so this just passes them through.
Clients that don't declare the matching ARGs ignore them (BuildKit drops
unused build args), same as COMMIT_HASH today.

Author: edg-l

.github/actions/deploy/action.yml

@@ -210,6 +210,9 @@ runs:
       build-args: |
         ${{ inputs.build_args }}
         COMMIT_HASH=${{ steps.git_commit_hash_full.outputs.git_commit_hash_full }}
+        GIT_SHA=${{ steps.git_commit_hash_full.outputs.git_commit_hash_full }}
+        GIT_BRANCH=${{ inputs.source_ref }}
+        VERSION=${{ inputs.source_ref }}-${{ steps.git_commit_hash.outputs.git_commit_hash }}
       labels: |
         ethpandaops.io.repo=${{ inputs.source_repository }}
         ethpandaops.io.commitRef=${{ inputs.source_ref }}