Document release process

Author: FooBarWidget

.github/workflows/ci-cd.yml

@@ -1,7 +1,9 @@
 name: CI/CD
 
 on:
-  push: {}
+  push:
+    paths-ignore:
+      - '*.md'
   workflow_dispatch:
     inputs:
       create_release:

CONTRIBUTING.md

@@ -14,3 +14,10 @@ Then run the test suite with:
 ~~~bash
 bundle exec rspec
 ~~~
+
+## Release process
+
+ 1. Bump the version number in `version.rb`.
+ 2. Ensure [the CI](https://github.com/FooBarWidget/distributed-lock-google-cloud-storage-ruby/actions) is successful.
+ 3. [Manually run the "CI/CD" workflow](https://github.com/FooBarWidget/distributed-lock-google-cloud-storage-ruby/actions/workflows/ci-cd.yml). Set the `create_release` parameter to `true`. Wait until it finishes. This creates a draft release.
+ 4. Edit [the draft release](https://github.com/FooBarWidget/distributed-lock-google-cloud-storage-ruby/releases)'s notes and finalize the release.