Change docker workflow for latest_release tag (#2468)

          tags: pyfound/black:latest,pyfound/black:${{ env.GIT_TAG }}

      - name: Build and push latest_release tag

        if: ${{ github.event_name == 'release' && github.event.action == 'created' }}

        if: ${{ github.event_name == 'release' && github.event.action == 'published' }}

        uses: docker/build-push-action@v2

        with:

          context: .