* Update arduino-pico core
* RP2040: Add mDNS support
* SimpleMDNS `begin` now returns a bool
* Add `-g` option to `debug_build_flags` to link files for gdb
* RAK11310 needs old platform as well
* Change defines to specific architecture
* Core version 4.2.1 is out
* update radiolib to 7.1.0
* stay at 7.0.2 for STM32, also remove unused board from ESP32 arch
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Co-authored-by: Ben Meadors <benmmeadors@gmail.com>