Increment skip to avoid infini-loop (#13703)

Signed-off-by: jolheiser <john.olheiser@gmail.com>

Co-authored-by: Lauris BH <lauris@nix.lv>

services/pull/pull.go

@@ -610,7 +610,7 @@ func GetCommitMessages(pr *models.PullRequest) string {
 				}
 				element = element.Next()
 			}
-
+			skip += limit
 		}
 	}