fix: Retry does not support kw allowable_methods

when initializing the ApiClient, the Retry object does not allow for keyword allowable methods

src/coscine/client.py

@@ -329,8 +329,7 @@ class ApiClient:
         retrycfg = Retry(
             total=retries,
             backoff_factor=1.0,
-            status_forcelist=[502, 503, 504],
-            allowed_methods={"GET"}
+            status_forcelist=[502, 503, 504]
         )
         self.session.mount("https://", HTTPAdapter(max_retries=retrycfg))
         self.verbose = verbose