Sync files with networkservicemesh/cmd-template

This PR syncs files with https://github.com/networkservicemesh/cmd-template

Revision: https://github.com/networkservicemesh/cmd-template/commits/a56f245c851bc34228aa6e6c907e8ebd0032e065

commit a56f245c851bc34228aa6e6c907e8ebd0032e065
Author: Ed Warnicke <hagbard@gmail.com>
Date:   Tue Jun 1 15:23:50 2021 -0500

    Add support for pushing to ghcr repos (#72)

Signed-off-by: NSMBot <nsmbot@networkservicmesh.io>

.github/workflows/docker-push-ghcr.yml

@@ -0,0 +1,40 @@
+---
+name: docker-push-ghcr
+
+on:
+  push:
+    branches: [main]
+
+jobs:
+  docker:
+    runs-on: ubuntu-latest
+    steps:
+      - name: "Checkout"
+        uses: actions/checkout@v2
+
+      - name: "Set up Docker Buildx"
+        uses: docker/setup-buildx-action@v1
+
+      - name: "Login to GitHub Container Registry"
+        uses: docker/login-action@v1
+        with:
+          registry: ghcr.io
+          username: ${{ github.repository_owner }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Docker meta
+        id: metaci
+        uses: docker/metadata-action@v3
+        with:
+          images: ghcr.io/${{ github.repository_owner }}/${{ github.event.repository.name }}/ci
+          tags: |
+            type=ref,event=pr
+            type=sha,prefix=
+
+      - name: "Build and push"
+        uses: docker/build-push-action@v2
+        with:
+          file: Dockerfile
+          context: .
+          push: true
+          tags: ${{ steps.metaci.outputs.tags }}