Add Jira example docs

Author: aschbacd

README.md

@@ -25,6 +25,31 @@ jobs:
         uses: aschbacd/[email protected]
 ```
 
+### Example configuration for Jira
+
+If you want to allow Jira issue ids at the beginning of the commit message / pull request title you
+can use the following configuration. With this configuration commit messages / pull request titles
+like `[GLA-1] Add sample file` as well as `Add sample file` will be valid.
+
+```yaml
+name: Linters
+
+on:
+  pull_request: {}
+  push: {}
+
+jobs:
+  gitlint:
+    runs-on: ubuntu-latest
+    name: GitLint
+    steps:
+      - name: Lint commits, branches, and pull requests
+        uses: aschbacd/[email protected]
+        with:
+          re-commit-message-subject: ^(\[[A-Z]+\-[0-9]+\] )?[A-Z].*((?!\.).)$
+          re-pull-request-title: ^(\[[A-Z]+\-[0-9]+\] )?[A-Z].*((?!\.).)$
+```
+
 ## Customization
 
 The following input keys can be used in your GitHub Actions workflow (shown above).