Add proto message for RepositoryService.ListMergedBranches

Signed-off-by: Rémy Coutable <remy@rymai.me>
2 jobs for rc/list-merged-branches in 4 minutes and 56 seconds (queued for 4 minutes and 53 seconds)
latest
Status Job ID Name Coverage
  Test
passed #37992135
build

00:03:53

passed #37992136
check-grpc-proto-clients

00:04:56