Enable pylint checks (#4092)

* pylint: enable checks for imports

* ci: add github action for pylint

* enable pylint on pre-commit

* Install requirements

* use local pylint installation rather than of pre-commit's

* fix import errors

* more checks

* Silence unused imports

* Make a copy of dict

setup.py

@@ -9,7 +9,7 @@ from setuptools.command.build_py import build_py as _build_py
 # see https://github.com/ninjaaron/fast-entry_points.
 # This saves about 200 ms on startup time for non-wheel installs.
 try:
-    import fastentrypoints  # noqa: F401
+    import fastentrypoints  # noqa: F401, pylint: disable=unused-import
 except ImportError:
     pass  # not able to import when installing through pre-commit
 
@@ -127,6 +127,7 @@ tests_requirements = [
     "flake8-bugbear",
     "flake8-comprehensions",
     "flake8-string-format",
+    "pylint",
 ]
 
 if (sys.version_info) >= (3, 6):