Bump mypy from 0.942 to 0.950

Author: github-actions[bot]

requirements-lint.txt

@@ -5,6 +5,6 @@ mccabe==0.7.0
 pyflakes==2.4.0
 pydocstyle==6.1.1
 black==22.3.0
-mypy==0.942
+mypy==0.950
 types-pkg-resources==0.1.3
 -r requirements-test-withpsycopg.txt