update changelog

Author: reverbc

CHANGELOG.md

@@ -1,6 +1,9 @@
 # Changelog
 
 ## [Unreleased]
+## Added
+- W6402 `useless-pytest-mark-decorator`: add warning for [using pytest.mark on fixtures](https://docs.pytest.org/en/stable/reference.html#marks) (thanks to @DKorytkin)
+- W6403 `deprecated-positional-argument-for-pytest-fixture`: add warning for [positional arguments to pytest.fixture()](https://docs.pytest.org/en/stable/deprecations.html#pytest-fixture-arguments-are-keyword-only) (thanks to @DKorytkin)
 
 ## [1.0.3] - 2021-03-13
 ## Fixed