Small fix for newer flake8 compatibility.

Don't directly compare types, but instead use "is" instead.

Signed-off-by: Chris Lalancette <clalancette@gmail.com>

rosidl_parser/rosidl_parser/definition.py

@@ -108,7 +108,7 @@ class AbstractType:
     __slots__ = ()
 
     def __eq__(self, other):
-        return type(self) == type(other)
+        return type(self) is type(other)
 
 
 class AbstractNestableType(AbstractType):