Improve pre-commit workflow (#2602)

* feat: add `isort` to `pre-commit`

* ci: skip `__init__.py` file for `isort`

* ci: make `isort` mandatory in lint pipeline

* docs: add a section on Git hooks

* ci: check isort diff

* fix: isort from master branch

* docs: add pre-commit badge

* ci: update black + bandit versions

* feat: add PR template

* refactor: PR template

* ci: remove bandit

* docs: add Black badge

* ci: try to remove all `|| true` statements

* ci: remove lint_python job

- Remove `lint_python` CI job
- Move `pyupgrade` job to `pre-commit` workflow

* fix: avoid messing with typing

* docs: add a note on running `pre-cpmmit` manually

* ci: apply `pre-commit` to the whole codebase

tests/vector/test_shared_memory.py

@@ -1,22 +1,20 @@
-import pytest
-import numpy as np
-
 import multiprocessing as mp
-from multiprocessing.sharedctypes import SynchronizedArray
-from multiprocessing import Array, Process
 from collections import OrderedDict
+from multiprocessing import Array, Process
+from multiprocessing.sharedctypes import SynchronizedArray
+
+import numpy as np
+import pytest
 
-from gym.spaces import Tuple, Dict
 from gym.error import CustomSpaceError
-from gym.vector.utils.spaces import _BaseGymSpaces
-from tests.vector.utils import spaces, custom_spaces
-
+from gym.spaces import Dict, Tuple
 from gym.vector.utils.shared_memory import (
     create_shared_memory,
     read_from_shared_memory,
     write_to_shared_memory,
 )
-
+from gym.vector.utils.spaces import _BaseGymSpaces
+from tests.vector.utils import custom_spaces, spaces
 
 expected_types = [
     Array("d", 1),