Release 0.3.1 (#121)

* update changelog, bump version to 0.3.1

* fix flake8

pyHS100/smartplug.py

@@ -93,7 +93,7 @@ class SmartPlug(SmartDevice):
             return None
 
         return int(self.sys_info['brightness'])
-        
+
     @brightness.setter
     def brightness(self, value: int):
         """
@@ -110,7 +110,7 @@ class SmartPlug(SmartDevice):
             return None
 
         if not isinstance(value, int):
-            raise ValueError("Brightness must be integer, " 
+            raise ValueError("Brightness must be integer, "
                              "not of %s.", type(value))
         elif value > 0 and value <= 100:
             self.turn_on()