Add missing labels and remove unnecessary build-args (#188)

The metadata-action produces Docker labels automatically, with this change
we add the output of that step to the build.

GoReleaser already has the Version, Date and Commit hash info available,
so we don't need to pass them as parameters to the build.

Author: lucacome

.github/workflows/ci.yml

@@ -37,8 +37,6 @@ jobs:
     runs-on: ubuntu-20.04
     outputs:
       sha: ${{ steps.vars.outputs.sha }}
-      version: ${{ steps.vars.outputs.version }}
-      date: ${{ steps.vars.outputs.date }}
       go_path: ${{ steps.vars.outputs.go_path }}
     steps:
       - name: Checkout Repository
@@ -52,8 +50,6 @@ jobs:
         id: vars
         run: |
           echo "::set-output name=sha::$(echo ${GITHUB_SHA} | cut -c1-7)"
-          echo "::set-output name=version::$(grep "VERSION = " Makefile | cut -d " " -f 3)"
-          echo "::set-output name=date::$(date -u +"%Y-%m-%dT%H:%M:%SZ")"
           echo "::set-output name=go_path::$(go env GOPATH)"
       - name: Check if go.mod and go.sum are up to date
         run: |
@@ -195,24 +191,23 @@ jobs:
             type=edge
             type=ref,event=pr
             type=ref,event=branch,suffix=-rc,enable=${{ startsWith(github.ref, 'refs/heads/release') }}
+
       - name: Build Docker Image
         uses: docker/build-push-action@v3
         with:
           file: build/Dockerfile
           context: '.'
           target: goreleaser
           tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
           load: ${{ github.event_name == 'pull_request' }}
           push: ${{ github.event_name != 'pull_request' }}
           platforms: ${{ github.event_name != 'pull_request' && env.platforms || '' }}
           cache-from: type=gha
           cache-to: type=gha,mode=max
           pull: true
           no-cache: ${{ github.event_name != 'pull_request' }}
-          build-args: |
-            VERSION=${{ needs.vars.outputs.version }}
-            GIT_COMMIT=${{ needs.vars.outputs.sha }}
-            DATE=${{ needs.vars.outputs.date }}
+
       - name: Run Trivy vulnerability scanner
         uses: aquasecurity/[email protected]
         continue-on-error: true