Readme Update

[jasonjabbour]

I'm pretty sure the following command in the Readme ros2 run teleop_twist_keyboard teleop_twist_keyboard should be updated to ros2 run champ_teleop champ_teleop.py because of the package name here: https://github.com/anujjain-dev/unitree-go2-ros2/blob/0def4b1f8031516c59011b787af5db32799f7794/champ_teleop/package.xml#L3

[anujjain-dev]

@jasonjabbour Thanks for pointing this out. You are absolutely correct, one can use a champ teleoperation package for stable robot teleoperation. Using a champ teleop gives you a more stable gait with command velocity, while one using a standard teleop twist keyboard will also give you command velocity but with lesser stability.