point to docs and add a couple extra options

.github/workflows/pr-title-validate.yml

@@ -14,4 +14,4 @@ jobs:
     steps:
     - name: validate
       run: |
-        echo "${{ github.event.pull_request.title }}" | grep -Eq '^(feat|fix|chore|refactor|enhance)\(.*\):.*$' && (echo "Pass"; exit 0) || (echo "Incorrect Format"; exit 1)
+        echo "${{ github.event.pull_request.title }}" | grep -Eq '^(feat|fix|chore|refactor|enhance|test|docs)\(.*\):.*$' && (echo "Pass"; exit 0) || (echo "Incorrect Format. Please see https://go-vela.github.io/docs/community/contributing_guidelines/#development-workflow"; exit 1)