Format code with yapf

This commit fixes the style issues introduced in 6382c13 according to the output
from yapf.

Details: https://deepsource.io/gh/kokarare1212/librespot-python/transform/69dadbca-d159-4a13-a0ba-4cfbfe74193a/

librespot/core.py

@@ -1111,7 +1111,11 @@ class Session(Closeable, MessageListener, SubListener):
             sha1 = SHA1.new()
             sha1.update(device_id.encode())
             secret = sha1.digest()
-            base_key = PBKDF2(secret, username.encode(), 20, 0x100, hmac_hash_module=SHA1)
+            base_key = PBKDF2(secret,
+                              username.encode(),
+                              20,
+                              0x100,
+                              hmac_hash_module=SHA1)
             sha1 = SHA1.new()
             sha1.update(base_key)
             key = sha1.digest() + b"\x00\x00\x00\x14"