teamcity-nightly-workflow: only create nightly-test branch on upstream provider repo (#20678)

* Update teamcity-nightly-workflow.yaml

* Update .github/workflows/teamcity-nightly-workflow.yaml

Co-authored-by: Stephen Lewis (Burrows) <[email protected]>

---------

Co-authored-by: Stephen Lewis (Burrows) <[email protected]>

Author: BBBmau

.github/workflows/teamcity-nightly-workflow.yaml

@@ -14,7 +14,7 @@ on:
 
 jobs:
   rename-TC-nightly-branch:
-
+    if: github.repository == 'hashicorp/terraform-provider-google' || github.repository == 'hashicorp/terraform-provider-google-beta'
     runs-on: ubuntu-latest
     steps:
       - uses: actions/github-script@e69ef5462fd455e02edcaf4dd7708eda96b9eda0 # v7.0.0