Add time signature 1/4 (#387)

Author: joostlek

src/spotifyaio/models.py

@@ -570,6 +570,7 @@ class Mode(IntEnum):
 class TimeSignature(IntEnum):
     """Time signature of a track."""
 
+    ONE_FOUR = 1
     THREE_FOUR = 3
     FOUR_FOUR = 4
     FIVE_FOUR = 5