actions: push to Docker Hub

.github/workflows/build.yaml

@@ -1,13 +1,33 @@
 name: build
 on: [push, pull_request]
 jobs:
-  build:
-    name: build
+  docker:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v1
+      - name: Login to Docker Hub
+        uses: docker/login-action@v1
+        with:
+          username: ${{ secrets.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+      - name: Extract metadata (tags, labels) for Docker
+        id: meta
+        uses: docker/metadata-action@v3
+        with:
+          images: ribbybibby/ssl-exporter
+      - name: Build and push Docker image
+        uses: docker/build-push-action@v2
+        with:
+          context: .
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
+  snapshot:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v1
-      - name: Build the Docker image
-        run: docker build .
       - name: Set up Go
         uses: actions/setup-go@v1
         with:

README.md

@@ -28,10 +28,10 @@ metric indicates if the probe has been successful.
 ### Release process
 
 - Update the `VERSION` file in this repository and commit to master
-- [This github action](.github/workflows/release.yaml) will add a changelog and
-  upload binaries in response to a release being created in Github
-- Dockerhub will build and tag a new container image in response to tags of the
-  format `/^v[0-9.]+$/`
+- Create a release in Github prefixed with `v` and GH actions will:
+  - Add a changelog
+  - Upload binaries
+  - Build and push a Docker image
 
 ## Usage