Bump Car racing and Remove Car Racing Discrete (openai#2963)

* Allows a new RNG to be generated with seed=-1 and updated env_checker to fix bug if environment doesn't use np_random in reset

* Revert "fixed `gym.vector.make` where the checker was being applied in the opposite case than was intended to (openai#2871)"

This reverts commit 519dfd9.

* Remove bad pushed commits

* Fixed spelling in core.py

* Pins pytest to the last py 3.6 version

* Allow Box automatic scalar shape

* Add test box and change default from () to (1,)

* update Box shape inference with more strict checking

* Update the box shape and add check on the custom Box shape

* Removed incorrect shape type and assert shape code

* Update the Box and associated tests

* Move dependency error to inside the atari environment

* Update the gym version to v0.25.0

* Bump car racing and remove car racing discrete

Incremented the version to v24.1 (openai#2870)

Updated the gym version to v0.24 (openai#2839)

Update version.py

Update version.py

Updating MuJoCo docstrings (openai#2616)

* Changed Ant docstring

* Changed half cheetah docstring

* Changed Hopper docstring, modified formulations for Ant, HalfCheetah

* Changed humanoid docstring

* Changed HumanoidStandup, InvertedDoublependulum, InvertedPendulum docstrings

* Updated remaining docstrings, updated names of reward terms, added notes about info

Tests: don't use editable mode, use import-mode=append (openai#2429)

Updated registration.py (openai#2375)

* Updated registration.py

* Blacken

Bump version to 0.19.0

0.18.3 and release notes