Maintenance release

New features:

• Add support for KR-920 (Korea 920 MHz) in the region selection menu (#117).

• Add official library.properties fields for linking pre-compiled object and adds additional pins definitions for SX1276 radios (#128) (thanks to Kent Williams).

• Add source-level debugging support (#122).

Bug fixes:

• Adjust USB Vbus check values for Catena 461x platform. Define AU915 as well as AU921 for LMIC migration (#131).

• Fix link "warning: changing start of section .bss by 4 bytes" (#129).

Misc:

• Update issue template.