Add instructions for releasing

This PR adds instructions for creating releases.

README.md

@@ -25,3 +25,13 @@ Run the following to use the CLI:
 ```sh
 node ./dist/cli/index.js
 ```
+
+## Releasing
+
+Releases are manually created from the [Releases page](https://github.com/WATonomous/watcloud-emails/releases).
+CI will automatically build the tarball and publish it to the release page.
+Release notes can be auto-generated via the web interface.
+
+Please follow [semantic versioning](https://semver.org/) when creating tags for releases.
+Tags should be prefixed with `v` (e.g. `v1.0.0`).
+Version numbers less than `1.0.0` should be considered unstable and may have breaking changes in minor versions.