add future looking pull_request event to conditional

Scorecard currently has experimental support for the `pull_request`
trigger, so we want to allow analysis to be run for it in the future.

Signed-off-by: Spencer Schrock <sschrock@google.com>

code-scanning/scorecard.yml

@@ -21,8 +21,8 @@ jobs:
   analysis:
     name: Scorecard analysis
     runs-on: ubuntu-latest
-    # This action only works when run from the default branch
-    if: github.event.repository.default_branch == github.ref_name
+    # `publish_results: true` only works when run from the default branch. conditional can be removed if disabled.
+    if: github.event.repository.default_branch == github.ref_name || github.event_name == 'pull_request'
     permissions:
       # Needed to upload the results to code-scanning dashboard.
       security-events: write