fix ups and autopep8

Signed-off-by: Jess Frazelle <github@jessfraz.com>

kittycad/models/pong_enum.py

@@ -1,7 +1,8 @@
 from enum import Enum
 
-class PongEnum(str, Enum):
-	PONG = 'pong'
 
-	def __str__(self) -> str:
-		return str(self.value)
+class PongEnum(str, Enum):
+    PONG = 'pong'
+
+    def __str__(self) -> str:
+        return str(self.value)