Fix Missing Comma in install_requires of setup.py

[MarvinK]

Problem Description

In the rsl_rl project's setup.py file, there is a missing comma in the install_requires list between "numpy>=1.16.4" and "tensorboardX". This may cause pip installation to fail with the error: 'install_requires' must be a string or list of strings containing valid project/version requirement specifiers; Expected end or semicolon (after version specifier)

Steps to Reproduce

1. Attempt to install rsl_rl using pip: cd rsl_rl && pip install -e .
2. Observe the failure in installation with the mentioned error message.

Expected Behavior

Correct the syntax error in setup.py to ensure all elements in the list are properly separated by commas.

Current Code

install_requires=[
    "torch>=1.4.0",
    "torchvision>=0.5.0",
    "numpy>=1.16.4"    # Missing comma here
    "tensorboardX",
    "tensorboard",
    "tabulate",
]

Suggested Fix

install_requires=[
    "torch>=1.4.0",
    "torchvision>=0.5.0",
    "numpy>=1.16.4",   # Added comma
    "tensorboardX",
    "tensorboard",
    "tabulate",
]