add goreleaser

This makes cutting a new release infinitely easier

.github/workflows/release.yaml

@@ -0,0 +1,26 @@
+name: release
+
+on:
+  release:
+    types:
+      - created
+jobs:
+  release:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+      - name: Unshallow
+        run: git fetch --prune --unshallow
+      - name: Set up Go
+        uses: actions/setup-go@v1
+        with:
+          go-version: 1.13.x
+      - name: Run GoReleaser
+        uses: goreleaser/goreleaser-action@v1
+        with:
+          version: latest
+          args: release --rm-dist
+          key: ${{ secrets.YOUR_PRIVATE_KEY }}
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

README.md

@@ -48,11 +48,18 @@ Similarly to the blackbox_exporter, visiting
 will return certificate metrics for example.com. The `ssl_tls_connect_success`
 metric indicates if the probe has been successful.
 
-## Docker
+### Docker
 
     docker pull ribbybibby/ssl-exporter
     docker run -p 9219:9219 ribbybibby/ssl-exporter:latest <flags>
 
+### Release process
+
+- [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.]+$/`
+
 ## Flags
 
     ./ssl_exporter --help
@@ -202,12 +209,6 @@ For instance:
 In order to use the https client, targets must be provided to the exporter with
 the protocol in the uri (`https://<host>:<optional port>`).
 
-## Limitations
-
-I've only exported a subset of the information you could extract from a
-certificate. It would be simple to add more, for instance organisational
-information, if there's a need.
-
 ## Acknowledgements
 
 The overall structure and implementation of this exporter is based on the