Corrected RPC scope guideline

The in correct RPC scope level was indicated in the
readme. This change correctly specifies that a
"REPOSITORY" scoped RPC requires a target repo.
4 jobs for po-fix-scope-type in 2 minutes and 52 seconds (queued for 1 second)
Status Job ID Name Coverage
  Test
passed #218946887
build

00:02:52

passed #218946889
check-grpc-proto-clients

00:01:57

passed #218946891
danger-review

00:01:13

passed #218946886
test

00:02:00