Adds missing reserved field name

Signed-off-by: ChrisJBurns <[email protected]>

proto/minder/v1/minder.proto

@@ -952,6 +952,7 @@ message UpstreamRepositoryRef {
 
 message Repository {
     reserved 15;
+    reserved "registered";
     optional string id = 1; // This is optional when returning remote repositories
     optional Context context = 2;
     string owner = 3;