Merge pull request #3 from weaveworks/release

Add release steps

Author: yiannistri

.github/workflows/release.yaml

@@ -0,0 +1,48 @@
+on:
+  push:
+    tags: [v*.*.*]
+
+name: release
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - name: Install Go
+      uses: actions/setup-go@v2
+      with:
+        go-version: 1.17.x
+    - name: Checkout code
+      uses: actions/checkout@v2
+      with:
+        fetch-depth: 0
+        ref: ${{ github.event.pull_request.head.sha }}
+    - name: Build docker image
+      run: |
+        make docker-build
+    - name: Login to Docker Hub
+      uses: docker/login-action@v1
+      with:
+        registry: docker.io
+        username: ${{ secrets.WGE_DOCKER_IO_USER }}
+        password: ${{ secrets.WGE_DOCKER_IO_PASSWORD }}
+    - name: Push image to docker registry
+      run: |
+        make docker-push
+
+  release:
+    if: startsWith(github.ref, 'refs/tags/')
+    runs-on: ubuntu-latest    
+    needs: build
+    steps:
+    - name: Build changelog
+      id: github_release
+      uses: mikepenz/release-changelog-builder-action@v2
+      env:
+        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+    - name: Release
+      uses: softprops/action-gh-release@v1
+      if: startsWith(github.ref, 'refs/tags/')
+      with:
+        prerelease: true
+        body: ${{steps.github_release.outputs.changelog}}
+