add documentation on how to make a release (#219)

docs/maintainers.md

@@ -0,0 +1,19 @@
+## Maintainer docs
+
+This documentation is targeting maintainers of the Dependabot CLI.
+
+### Creating a release
+
+- Go to https://github.com/dependabot/cli/releases
+- Click `Draft a new release`
+- Click `Choose a tag`
+- In the input, type `v1.<minor>.<patch>` choosing the next minor or patch
+   - It really doesn't matter much which one you bump, but if it's a fix to the previous release patch makes sense.
+   - Don't bump the major version unless there were large breaking changes.
+-  Click `Generate release notes`
+   - If you want, you can delete lines that are minor like changes to workflows, README typo fixes, etc.  
+-  Click `Publish release`
+-  Monitor the [Release binary builder](https://github.com/dependabot/cli/actions/workflows/release.yml)https://github.com/dependabot/cli/actions/workflows/release.yml, it sometimes fails and needs to re-run
+
+ If anything goes wrong, like you've typed in something non-sensical as the version number by mistake, just delete the release/tag and create a new one.
+