3.6.0b1

Added

• Allow Bluetooth to be toggled off and on with the Bluetooth button on the
  Prime Hub and the Inventor Hub (support#1615), and have this state persist
  between reboots.
• Added heading_correction to hub.imu.settings to allow for automatic
  correction of the hub.imu.heading() value (support#1678).
• Added update_heading_correction to interactively set the heading
  correction value (support#1678).
• Added optional one byte program identifier to program start command.
  For now, this is added to start various builtin
  programs, but it prepares for the ability to start different downloaded
  programs too (pybricks-micropython#254).
• Added one byte program identifier to the hub status report to the host.
• Added interface and implementation for storing and selecting multiple code
  slots on the Prime Hub and Inventor Hub.
• Added ability to set distance and angle in DriveBase.reset(). If the
  DriveBase is using the gyro, it will be set to the same angle. (support#1617).
• Added DriveBase.arc method with more intuitive parameters to drive along
  an arc, to eventually replace DriveBase.curve (support#1157).

Changed

• Changed protocol to Pybricks Profile v1.4.0.
• When upgrading the firmware to a new version, the user program will now
  be erased. This avoids issues with incompatible program files (support#1622).
• The angular_velocity_threshold, and acceleration_threshold settings
  in hub.imu.settings are now persistent between reboots.
• Reduced hub poweroff time from 3 to 2 second to make it easier to turn off
  the hub (pybricks-micropython#250).
• Improved font for the digits 0--9 when displaying them
  with hub.display.char(str(x)) (pybricks-micropython#253).
• On SPIKE Prime Hub and Robot Inventor Hub, moved Bluetooth indications to
  the Bluetooth light. Only warning lights will be shown on the main button
  light. See (support#1716) and (pybricks-micropython#261).
• Allow gyro calibration only while all motors are coasting (support#1840) to
  prevent recalibration during very steady moves (support#1687)
• Reduced default angular velocity stationary threshold from an undocumented
  5 deg/s to 3 deg/s to reduce unwanted calibration while moving (support#1105).
• If imu.reset_heading() is called while a drive base is actively using the
  gyro, an exception will be raised (support#1818).

Fixed

• Fixed not able to connect to new Technic Move hub with LWP3Device().
• Removed gc_collect() from tools.run_task() loop to fix unwanted delays.
• Fixed await wait(0) never yielding, so parallel tasks could lock up (support#1429).

Removed

• Removed loop_time argument to pybricks.tools.run_task as this wasn't
  having the desired effect, and would cause loop round trips to take 10 ms
  for every await wait(1) (support#1460). This was an undocumented feature.