Update github actions

.github/workflows/release.yml

@@ -0,0 +1,58 @@
+name: Releases
+
+on:
+  release:
+    types: [published]
+
+jobs:  
+  release:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+
+    - name: Set up JDK 1.8
+      uses: actions/setup-java@v1
+      with:
+        java-version: 1.8
+
+    - name: Grant execute permission for gradlew
+      run: chmod +x gradlew
+
+    - name: Build with Gradle
+      run: ./gradlew build
+
+    - name: Release
+      uses: fnkr/github-action-ghr@v1
+      env:
+        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        GHR_PATH: "build/libs/"
+
+    - name: Generate Docker metadata
+      id: meta
+      uses: docker/metadata-action@v3
+      with:
+        images: |
+          criteord/cassandra_exporter
+        tags: |
+          type=ref,event=branch
+          type=semver,pattern={{version}}
+          type=semver,pattern={{major}}.{{minor}}
+        flavor: |
+          latest=true
+
+    - name: Login to Docker Hub
+      uses: docker/login-action@v1
+      with:
+        username: ${{ secrets.DOCKER_USERNAME }}
+        password: ${{ secrets.DOCKER_PASSWORD }}
+
+    - name: Set up Docker Buildx
+      uses: docker/setup-buildx-action@v1
+
+    - name: Build and push
+      uses: docker/build-push-action@v2
+      with:
+        context: .
+        file: docker/Dockerfile
+        push: true
+        tags: ${{ steps.meta.outputs.tags }}