mrhlpr.mr: Increase automerge retry iterations to 10

This seems to help with more reliably getting automerge going on the new
GitLab instance … maybe.

mrhlpr/mr.py

@@ -564,7 +564,7 @@ def finish(
         print("Adding the comment...")
         mr.notes.create({"body": comment})
 
-    iterations: Final[int] = 5
+    iterations: Final[int] = 10
     sleep_time: Final[int] = 5
     # Proper stupid but it works. Originally I had this set to a maximum of 15 seconds
     # of sleepy time, but for gitlab.postmarketos.org this wasn't always sufficient to catch up.