chore: Make Codecov status checks informational (#1662)

Coverage checks will still post comments and show status on PRs,
but will never block merging. Coverage is enforced by the CI
threshold check in test.yml, not by Codecov status checks.

Co-authored-by: Ben Coombs <bjcoombs@users.noreply.github.com>

Author: bjcoombs

codecov.yml

@@ -4,9 +4,11 @@ coverage:
       default:
         target: 50%
         threshold: 2%
+        informational: true
     patch:
       default:
         target: 60%
+        informational: true
 
 ignore:
   - "**/*.pb.go"