Fix alg matching in pick_key

Author: janste63

src/cryptojwt/__init__.py

@@ -16,7 +16,7 @@
 
 from binascii import unhexlify
 
-__version__ = '0.3.0'
+__version__ = '0.3.1'
 
 logger = logging.getLogger(__name__)
 

src/cryptojwt/jwt.py

@@ -43,7 +43,7 @@ def pick_key(keys, use, alg='', key_type='', kid=''):
             continue
 
         if key.kty == key_type:
-            if key.alg == '' or key.alg == alg:
+            if key.alg == '' or alg == '' or key.alg == alg:
                 if key.kid == '' or kid == '' or key.kid == kid:
                     res.append(key)
     return res