Update repo settings (#1846)

Author: trask

.github/repository-settings.md

@@ -2,5 +2,6 @@
 
 Same
 as [opentelemetry-java-instrumentation repository settings](https://github.com/open-telemetry/opentelemetry-java-instrumentation/blob/main/.github/repository-settings.md#repository-settings),
-except that the rules for `gh-pages` and `cloudfoundry` branches are not relevant in this
-repository.
+except for
+* The rules for `gh-pages` and `cloudfoundry` branches are not relevant in this repository.
+* "Restrict branch creation" includes an exclusion for `gh-readonly-queue/main/pr-*`.