avrtos v1.2.1

Key features:

• I2C:
  • Introduce function i2c_master_write_read() enabling to write and
    read data in a single transaction.
  • Rename i2c_master_transmit()) to i2c_master_write().
  • Rename i2c_master_receive() to i2c_master_read().
  • Add option to configure the speed of the I2C bus on initialization.

Minor changes:

• Introduce CONFIG_KERNEL_REENTRANCY configuration option to enable/disable
  reentrancy support for kernel objects, such as mutexes and sched lock/unlock.
• Change code style, update .clang-format and format the codebase.
• Improve stack sentinel verification by introducing a thread monitoring mecanism.
• Introduce CONFIG_THREAD_MONITOR and CONFIG_THREAD_MAIN_MONITOR configuration
  options to enable/disable thread monitoring.
• Introduce CONFIG_THREAD_STACK_SENTINEL_AUTO_VERIFY configuration option to
  enable/disable automatic stack sentinel verification.
• Improve timers subsystem.

Bug fixes:

• Fix returned error code in i2c_master_write() and i2c_master_read().
• Fix K_MSEC macro with big values of CONFIG_KERNEL_SYSCLOCK_PERIOD_US.
• Fix K_WORK_DELAYABLE_INIT macro.

Full Changelog: v1.2.0...v1.2.1