Add release workflow

.github/workflows/release.yaml

@@ -0,0 +1,30 @@
+name: release
+
+on:
+  push:
+    tags:
+      - "v*"
+
+jobs:
+  push:
+    runs-on: buildjet-4vcpu-ubuntu-2004
+    steps:
+      - uses: actions/checkout@v3
+      - uses: acorn-io/actions-login@v1
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+      - name: Set tag
+        run: |
+          echo "TAG=${GITHUB_REF#refs/tags/}" >> $GITHUB_ENV
+          echo "DRONE_TAG=${GITHUB_REF#refs/tags/}" >> $GITHUB_ENV
+          echo "REPO=ghcr.io/acorn-io" >> $GITHUB_ENV
+      - name: Build and push rancher
+        run: |
+          set -e
+          make .dapper
+          ./.dapper sh -c './scripts/build && ./scripts/package' || true
+          docker push ghcr.io/acorn-io/rancher:$TAG
+          docker push ghcr.io/acorn-io/rancher-agent:$TAG
+          docker push ghcr.io/acorn-io/rancher-runtime:$TAG