ci: add CLA

Author: rubenfiszel

.github/workflows/sign-cla.yml

@@ -15,7 +15,7 @@ jobs:
         uses: cla-assistant/[email protected]
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-          PERSONAL_ACCESS_TOKEN: ${{ secrets.PAT }}
+          PERSONAL_ACCESS_TOKEN: ${{ secrets.CLA_PAT }}
         with:
           path-to-signatures: "signatures/cla.json"
           path-to-document: "https://github.com/windmill-labs/windmill/blob/master/CLA.md"