Update dependency gym to v0.18.3

[renovate]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
gym	==0.18.0 -> ==0.18.3

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Release Notes

openai/gym

v0.18.3

Compare Source

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[github-actions]

✅ Result of Pytest Coverage

---------- coverage: platform linux, python 3.7.10-final-0 -----------

Name	Stmts	Miss	Cover
simzoo/init.py	10	1	90%
simzoo/common/init.py	7	3	57%
simzoo/common/disturbances.py	14	10	29%
simzoo/common/disturber.py	371	329	11%
simzoo/common/helpers.py	79	68	14%
simzoo/envs/init.py	0	0	100%
simzoo/envs/biological/init.py	7	3	57%
simzoo/envs/biological/oscillator/init.py	7	3	57%
simzoo/envs/biological/oscillator/oscillator.py	104	59	43%
simzoo/envs/biological/oscillator/oscillator_disturber.py	18	8	56%
simzoo/envs/classic_control/init.py	10	5	50%
simzoo/envs/classic_control/cart_pole_cost/init.py	7	3	57%
simzoo/envs/classic_control/cart_pole_cost/cart_pole_cost.py	218	191	12%
simzoo/envs/classic_control/cart_pole_cost/cart_pole_cost_disturber.py	19	10	47%
simzoo/envs/classic_control/ex3_ekf/init.py	7	3	57%
simzoo/envs/classic_control/ex3_ekf/ex3_ekf.py	99	60	39%
simzoo/envs/classic_control/ex3_ekf/ex3_ekf_disturber.py	19	8	58%
tests/test_envs_register.py	14	3	79%
TOTAL	1010	767	24%
Coverage	HTML	written	to
=========================	3	passed,	1