Wrap the repository name in codeowner checker

It currently is causing syntax error.

Author: saschanaz

.github/workflows/codeowners-merge.yml

@@ -12,10 +12,10 @@ jobs:
       - uses: actions/checkout@v1
       - name: Run Codeowners merge check
         uses: OSS-Docs-Tools/code-owner-self-merge@1.5.4
-        if: github.repository == microsoft/TypeScript-DOM-lib-generator
+        if: github.repository == 'microsoft/TypeScript-DOM-lib-generator'
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
         with:
           merge_method: 'squash'
           if_no_maintainers_add_label: 'maintainers'
-          if_no_maintainers_assign: '@orta @sandersn'
+          if_no_maintainers_assign: '@orta @sandersn'