randomize maze environments temporary xml file name

[Kallinteris-Andreas]

Description

fixes issue #184 by assigning a unique name to all temporary asset files

Fixes # (issue)

Type of change

• Bug fix (non-breaking change which fixes an issue)

Checklist:

• I have run the pre-commit checks with pre-commit run --all-files (see CONTRIBUTING.md instructions to set it up)
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[rodrigodelazcano]

Hey @Kallinteris-Andreas thanks for the PR. Are there any other environments that require creating unique xml file names? The mamujoco environments do create custom xml's at runtime, does jinja already solve this issue?

[Kallinteris-Andreas]

mamjoco is affected by the same issue, i will make a PR later for mamujoco-v1 (it will be small release to update to gymnasium/mujoco-v5)