Add --gym-packages parameter to push_to_hub

[ernestum]

Description

Adds a --gym-packages parameter to the rl_zoo3.push_to_hub command just like with the rl_zoo3.train command.

Motivation and Context

For the rl_zoo3.train command line there is the --gym-packages parameter to allow for importing foreign gym packages.
When you want to upload the trained model to HuggingFace this will fail since the rl_zoo3.push_to_hub command has no such parameter and therefore the upload script won't be able to create an environment to render a preview for HuggingFace.

• 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 reformatted the code using make format (required)
• I have checked the codestyle using make check-codestyle and make lint (required)
• I have ensured make pytest and make type both pass. (required)

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[araffin]

It seems that the commited changes do not correspond to the described feature, no?

EDIT: otherwise, this is indeed a needed feature.