merge v1.3.0 into master

[bxparks]

• 1.3.0 (2023-07-20)
  • Replace call to Epoch::daysToCurrentEpochFromConverterEpoch() with
    Epoch::daysToCurrentEpochFromInternalEpoch(), to be consistent with
    AceTime v2.3.0.
    • This an internal implementation detail, it should not cause an API
      breakage.
  • Upgrade tool chain
    • Upgrade Arduino CLI to 0.33.0.
    • Upgrade Arduino AVR Core to 1.8.6.
    • Upgrade STM32 Core to 2.6.0.
    • Upgrade ESP32 Core to 2.0.9.
    • Upgrade Teensyduino from 1.56 to 1.57.
  • Update supported boards and tiers
    • Add SAMD21 and SAMD51 boards to Tier 1
      • Add 2 SAMD boards from 2 different companies, to test their
        Arduino Board software:
        • Seeeduino XIAO M0 (SAMD21 48MHz ARM Cortex-M0+)
        • Adafruit ItsyBitsy M4 (SAMD51 120MHz ARM Cortex-M4)
      • SAMD21 and SAMD51 boards are back in Tier 1, as long as they use
        the traditional Arduino API instead of the new
        ArduinoCore-api.
      • Fortunately most third party SAMD21 and SAMD51 boards continue to
        use the traditional Arduino API.
    • Move Teensy 3.2 to Tier 2 ("Should work but not tested often")
      • This board is entering end-of-life.
      • As well, the Teensyduino environment integrates with the Arduino
        IDE and CLI in a way that's different than all other third-party
        Arduino boards. Some of my automation scripts do not work with
        Teensyduino, so it becomes very time consuming to test the Teensy
        boards.
      • All Teensy boards are now in Tier 2 .