Update GitHub Actions workflows. (#1269)

This PR was automatically generated by the
update-workflows-ecosystem-providers workflow in the pulumi/ci-mgmt
repo, from commit 49ef383ad13f781d52773c9fd9d15cec49362a92.

.github/workflows/upgrade-bridge.yml

@@ -6,7 +6,7 @@ env:
 jobs:
   upgrade_provider:
     name: upgrade-provider
-    runs-on: ubuntu-latest
+    runs-on: pulumi-ubuntu-8core
     steps:
     - name: Call upgrade provider action
       uses: pulumi/[email protected]