Fix get_fork for Pagure (#800)

Fix get_fork for Pagure

When getting the fork from existing forks, check for equality of the usernames and not only substring check with 'in' operator. This prevents getting a fork of 'packit-stg' for user 'packit'.
Fixes packit/packit-service#2178
RELEASE NOTES BEGIN
We have fixed a bug in get_fork method for Pagure about checking the usernames for a match when going through existing forks.
RELEASE NOTES END

Reviewed-by: Matej Focko

ogr/services/pagure/project.py

@@ -302,7 +302,7 @@ def get_fork(self, create: bool = True) -> Optional["PagureProject"]:
 
         for fork in self.get_forks():
             fork_info = fork.get_project_info()
-            if self._user in fork_info["user"]["name"]:
+            if self._user == fork_info["user"]["name"]:
                 return fork
 
         if not self.is_forked():