doc(example): set permissions and only post on pr

Update the example so it only attempts to post comments on the PR action
and set the permissions fields to the minimum values required to leave
comments on PRs.

Signed-off-by: Randolph Sapp <rs@ti.com>

Author: StaticRocket

README.md

@@ -23,20 +23,25 @@ on:
 jobs:
   commit-check:
     runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      issues: write
+      pull-requests: write
     steps:
       - uses: actions/checkout@v4
         with:
           ref: ${{ github.event.pull_request.head.sha }} # Checkout PR HEAD commit
       - uses: commit-check/commit-check-action@v1
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
         with:
           message: true
           branch: true
           author-name: true
           author-email: true
           commit-signoff: true
-          dry-run: true
           job-summary: true
-          pr-comments: true
+          pr-comments: ${{ github.event_name == 'pull_request' }}
 ```
 
 ## Optional Inputs