doorcontrol: Explicity cast Credential.bits to Bits, as Bitstream is not hashable

doorcontrol/hid/Credential.py

@@ -34,7 +34,7 @@ class Credential:
         )
         bits[6] = bits[7:19].count(1) % 2  # even parity
         bits[31] = bits[19:31].count(0) % 2  # odd parity
-        return cls(bits)
+        return cls(bitstring.Bits(bits))
 
     @classmethod
     def from_hex(cls, hex_code: str) -> "Credential":