CommitService::FindCommit RPC Design

~Conversation: #321 (closed)

Taken from @jacobvosmaer-gitlab's proposal:

service CommitService {
  rpc FindCommit(FindCommitRequest) returns (FindCommitResponse);
}

message FindCommitRequest {
  Repository repository = 1;
  bytes revision = 2;
}

message FindCommitResponse {
  // commit is nil when the commit was not found
  GitCommit commit = 1;
}