asserts: fix annoying py35 syntax error

Author: bluetech

Diff for: pytest_django/asserts.py

@@ -116,15 +116,15 @@ def assertRaisesMessage(
         expected_exception: BaseException,
         expected_message: str,
         *args,
-        **kwargs,
+        **kwargs
     ):
         ...
 
     def assertWarnsMessage(
         expected_warning: Warning,
         expected_message: str,
         *args,
-        **kwargs,
+        **kwargs
     ):
         ...
 
@@ -202,7 +202,7 @@ def assertNumQueries(
         func=...,
         *args,
         using: str = ...,
-        **kwargs,
+        **kwargs
     ):
         ...