Python: Document pinning dependency versions

[daltzctr]

Instead of robotpy_extras, pinned versions can be declared in the requires block in pyproject.toml

#
# Use this configuration file to control what RobotPy packages are installed
# on your RoboRIO
#

[tool.robotpy]

# Version of robotpy this project depends on
robotpy_version = "2024.2.1.0"

# Which extra RobotPy components should be installed
# -> equivalent to `pip install robotpy[extra1, ...]
robotpy_extras = [
    # "all"
    # "apriltag"
    # "commands2"
    # "cscore"
    # "navx"
    # "pathplannerlib"
    # "phoenix5"
    # "playingwithfusion"
    # "rev"
    # "romi"
    # "sim"
]

requires = [
   "phoenix6==24.3.0",
]