MuJoCo MJX Support - Add Robotiq 2f85 V4 model

[peterdavidfagan]

This pull request accomplishes the following:

1. Updates the commit hash for the mujoco_menagerie library to the latest
2. Adds the robotiq_2f85_v4 model

[stephane-caron]

Thank you for starting this 👍 There are a couple of small things to wrap this up, like updating _descriptions.py or the changelog. You can check the step-by-step list in CONTRIBUTING.md.

[coveralls]

Pull Request Test Coverage Report for Build 13159372593

Details

• 6 of 6 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.02%) to 97.454%

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Totals
Change from base Build 12652899350:	0.02%
Covered Lines:	957
Relevant Lines:	982

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💛 - Coveralls

[peterdavidfagan]

Thank you for starting this 👍 There are a couple of small things to wrap this up, like updating _descriptions.py or the changelog. You can check the step-by-step list in CONTRIBUTING.md.

Ah yes my bad I'll update this now, originally it was a very quick/messy pass on my side as I was making this change on my local version.

[stephane-caron]

LGTM, thank you for adding this description 👍