Use new endpoint for gestdown (#1949)

This endpoint rely on caching from cloudflare and will better scale.

Right now, I'm getting around 3M request per day, so I'd like to use the caching as much as possible.

libs/subliminal_patch/providers/gestdown.py

@@ -84,13 +84,10 @@ class GestdownProvider(Provider):
         self._session.close()
 
     def _subtitles_search(self, video, language: Language):
-        json_data = {
-            "search": f"{video.series} S{video.season:02}E{video.episode:02}",
-            "language": self._converter.convert(language.alpha3),
-        }
 
         logger.debug("Post data: %s", json_data)
-        response = self._session.post(f"{_BASE_URL}/subtitles/search", json=json_data)
+        lang = self._converter.convert(language.alpha3)
+        response = self._session.get(f"{_BASE_URL}/subtitles/find/{lang}/{video.series}/{video.season}/{video.episode}")
 
         # TODO: implement rate limiting
         response.raise_for_status()