Bump pytest from 5.3.4 to 5.3.5 (#262)

Author: dependabot-preview[bot]

requirements/requirements_dev.txt

@@ -10,7 +10,7 @@ hypothesis==4.53.1
 placebo==0.9.0
 pre-commit==1.21.0
 pylint==2.4.4
-pytest==5.3.4
+pytest==5.3.5
 pytest-black==0.3.7
 pytest-cov==2.8.1
 pytest-datadir==1.3.1