support cdn-converted webp media

dist/webshot.js

@@ -56,7 +56,7 @@ class Webshot extends CallableInstance {
             }
             logger.warn('unable to find MIME type of fetched media, failing this fetch');
             throw Error();
-        })(/\/.*\.(.+?)\?/.exec(url)[1]));
+        })(/\/.+\.(?:.*?(?<=[?&])stp=dst-(jpg)|(.+?)\?)/.exec(url).filter(g => g)[1]));
         onready();
     }
     webshot(mediaItems, callback, webshotDelay) {

src/webshot.ts

@@ -62,7 +62,7 @@ class Webshot extends CallableInstance<[MediaItem[], (...args) => void, number],
       }
       logger.warn('unable to find MIME type of fetched media, failing this fetch');
       throw Error();
-    })(/\/.*\.(.+?)\?/.exec(url)[1])
+    })(/\/.+\.(?:.*?(?<=[?&])stp=dst-(jpg)|(.+?)\?)/.exec(url).filter(g => g)[1])
   );
 
   public webshot(