Upgrade to v2 of the Docker GitHub action (#784)

* Upgrade to v2 of the Docker GitHub action

* Add context and file

* Fix build args

* cleanup

Author: kyleconroy

.github/workflows/docker.yml

@@ -1,22 +1,32 @@
 name: docker
-
 on:
   push:
     branches:
     - master
-
 jobs:
-
   docker:
     name: push kjconroy/sqlc:devel
     runs-on: ubuntu-latest
     steps:
+    - name: Set created date
+      id: prep
+      run: |
+        echo ::set-output name=created::$(date -u +'%Y-%m-%dT%H:%M:%SZ')
     - uses: actions/checkout@v2
-    - uses: docker/build-push-action@v2.1.0
+    - uses: docker/setup-buildx-action@v1
+    - uses: docker/login-action@v1
       with:
         username: kjconroy
         password: ${{ secrets.DOCKER_PASSWORD }}
-        build_args: github_ref=${{ github.ref }},github_sha=${{ github.sha }}
-        repository: kjconroy/sqlc
-        add_git_labels: true
-        tags: devel
+    - uses: docker/build-push-action@v2
+      with:
+        context: .
+        file: ./Dockerfile
+        build-args: |
+          github_ref=${{ github.ref }}
+          github_sha=${{ github.sha }}
+        tags: kjconroy/sqlc:devel
+        labels: |
+          org.opencontainers.image.source=${{ github.event.repository.html_url }}
+          org.opencontainers.image.created=${{ steps.prep.outputs.created }}
+          org.opencontainers.image.revision=${{ github.sha }}