Bugfix: Fix failing test `test_read_holmgard_gym.py` (Resolve Issue #18)

[LJArendse]

Overview

This PR aims to address the failing test test_read_holmgard_gym.py. The _tests/envs/test_read_holmgardgym.py test fails on linux based filesystems. This is because linux based filesystems are "file-name case-sensitive". Please see Issue https://github.com/ganyariya/gym-md/issues/18 for detail.

Changes Made

Modify the def read_settings(stage_name: str) -> PropsConfig static method within the gym_md/envs/setting.py file to cater for the case-sensitive file names.

Testing output after changes

========================================= test session starts =========================================
platform linux -- Python 3.8.10, pytest-6.2.5, py-1.10.0, pluggy-1.0.0
rootdir: /home/***/***/gym-md
collected 20 items                                                                                    

tests/envs/test_change_rewards.py .                                                             [  5%]
tests/envs/test_config.py ...                                                                   [ 20%]
tests/envs/test_grid.py .                                                                       [ 25%]
tests/envs/test_gym.py ..                                                                       [ 35%]
tests/envs/test_path.py ..                                                                      [ 45%]
tests/envs/test_random.py .                                                                     [ 50%]
tests/envs/test_read_holmgard_gym.py ...                                                        [ 65%]
tests/envs/test_setting.py .                                                                    [ 70%]
tests/envs/agents/test_agent.py ......                                                          [100%]

========================================= 20 passed in 15.31s =========================================

[LJArendse]

Thanks for merging :+1: :100: