add the docker release workflow

Author: netcode

.github/workflows/ci.yaml

@@ -0,0 +1,43 @@
+name: Release docker image
+
+on:
+  push:
+    tags:
+      - "*"
+
+env:
+  REGISTRY: ghcr.io
+  IMAGE_NAME: datadog/appsec-threat-emulation
+
+permissions:
+  contents: read
+
+jobs:
+  docker-build-push:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2.5.0
+        with:
+          fetch-depth: 0
+
+      - name: Log into registry ${{ env.REGISTRY }}
+        uses: docker/login-action@v2.1.0
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Build and push Docker image
+        uses: docker/build-push-action@v3.2.0
+        with:
+          context: .
+          push: true
+          build-args: |
+            VERSION=${{ github.ref_name }}
+          tags: |
+            ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:${{ github.ref_name }}
+            ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:latest