• Remove custom_cartpole.py
• Remove calls to custom cartpole
• Deepq train custom cartpole doesn't work #810
• Error running custom_cartpole.py #812
• update changelog

Description

Delete the file stable_baselines\deepq\experiments\custom_cartpole.py
Delete calls made to the above deleted file intests\test_deepq.py
No other references to the deleted file were found.

Motivation and Context

This change is in direct response to problems seen in running custom_cartpole.py
As discussed in the comments of the both the issues discussing it, the file is being removed, along with any references made to it.

• closes Deepq train custom cartpole doesn't work #810
• closes Error running custom_cartpole.py #812
  The change is put under documentation section of change-log as discussed in the issue
• I have raised an issue to propose this change (required for new features and bug fixes)

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation (update in the documentation)

Checklist:

• I've read the CONTRIBUTION guide (required)
• I have updated the changelog accordingly (required).
• My change requires a change to the documentation.
• I have updated the tests accordingly (required for a bug fix or a new feature).
• I have updated the documentation accordingly.
• I have ensured pytest and pytype both pass (by running make pytest and make type).
  pytest and pytype not verified because running those, causes my laptop to throttle and hang. Since the changes are not part of functional code, I think it will be fine.