Update issue-labeler.yaml

updated to use the GITHUB_TOKEN secret instead of a custom secret that had to be explicitly created for the action/workflow.

.github/workflows/issue-labeler.yaml

@@ -15,7 +15,7 @@ jobs:
       - name: RegEx-based Issue Labeler
         uses: github/[email protected]
         with:
-          repo-token: "${{ secrets.REGEX_LABELER }}"
+          repo-token: "${{ secrets.GITHUB_TOKEN }}"
           configuration-path: .github/issue-labeler-config-regexes.yaml
           # from the third-party documentation:
           # not-before attribute is optional and will result in any issues prior to this timestamp to be ignored.