[extractors/podbayfm] Add extractor (#4971)

Authored by: schnusch

yt_dlp/utils.py

@@ -5499,7 +5499,8 @@ def jwt_encode_hs256(payload_data, key, headers={}):
 # can be extended in future to verify the signature and parse header and return the algorithm used if it's not HS256
 def jwt_decode_hs256(jwt):
     header_b64, payload_b64, signature_b64 = jwt.split('.')
-    payload_data = json.loads(base64.urlsafe_b64decode(payload_b64))
+    # add trailing ='s that may have been stripped, superfluous ='s are ignored
+    payload_data = json.loads(base64.urlsafe_b64decode(f'{payload_b64}==='))
     return payload_data