Fix file type check in PR checker workflow

Signed-off-by: Timothy Johnson <timothy.johnson@broadcom.com>

.github/workflows/pull-request-checker.yml

@@ -69,10 +69,12 @@ jobs:
             If you have addressed this issue already, refresh this page in your browser to remove this comment.
       - name: File type checker
         id: file_type_checker
+        uses: actions/github-script@v6
         env:
           PR_BODY_PATTERN: '\.md|\.jpg|\.gif|\.png|\.pdf'
-        run: |
-          [[ "${{ github.event.pull_request.body }}" =~ "$PR_BODY_PATTERN" ]] || exit 1
+        with:
+          script: |
+            new RegExp(process.env.PR_BODY_PATTERN).test(context.payload.pull_request.body) || process.exit(1)
       - name: Missing File Name Comment PR
         if: failure() && steps.file_type_checker.outcome == 'failure'
         uses: marocchino/sticky-pull-request-comment@v2