[CI][Github] Do not fail premerge job

The postcommit job is currently sending emails on failures. A lot of these
emails are useless noise as there are still some problems with the new
infrastructure that need to be fixed before the results are reliable.

Author: boomanaiden154

.github/workflows/premerge.yaml

@@ -31,6 +31,12 @@ jobs:
       - name: Setup ccache
         uses: hendrikmuhs/[email protected]
       - name: Build and Test
+        # Mark the job as a success even if the step fails so that people do
+        # not get notified while the new premerge pipeline is in an
+        # experimental state.
+        # TODO(boomanaiden154): Remove this once the pipeline is stable and we
+        # are ready for people to start recieving notifications.
+        continue-on-error: true
         run: |
           git config --global --add safe.directory '*'