replace instead of adding in the hashtbl

src/osh.ml

@@ -113,7 +113,7 @@ let badge_github_workflow_status =
           | None -> Error "Invalid JSON answer"
           | Some x ->
             let status = x |> Util.member "conclusion" |> Util.to_string in
-            Hashtbl.add tbl url (status, Unix.time ());
+            Hashtbl.replace tbl url (status, Unix.time ());
             Ok status )
     in
     match status with