Add pr-labels feature docs

Author: squizzi

README.md

@@ -2,11 +2,14 @@
 Common workflows required for some or all replicatedhq repos
 
 ## Workflows
-* **pr-labels.yml**: Fails if a PR does not have the necessary labels for Engineering metrics
+* **pr-labels.yml**: Fails if a PR does not have the necessary labels for Engineering metrics, will apply primary labels if the PR title or `HEAD` commit message contains a semantic commit, for example:
+    * `feat(ci)`, `feature(ci)`: Adds `type::feature`
+    * `bug(ci)`: Adds `type::bug`
+    * `chore(ci)`: Adds `type::chore`
 
 ## Actions
 Any custom actions related to these workflows reside in `.github/actions`.
 
 JavaScript actions must have their `dist` folders rebuilt if changed. Run `npm run all` in the action folder before committing and pushing.
 
-* **pr-labels**: Implements the PR label check logic as outlined in the wiki.
+* **pr-labels**: Implements the PR label check logic as outlined in the wiki.