ci: update firmware hex files [skip ci]

Merge pull request #50 from BenGardiner/dont-clobber

don't clobber ECUX.hex files when copying

ci: update firmware hex files [skip ci]

Merge pull request #49 from BenGardiner/copy-more-hex-files

copy the .hex files with a find command

ci: update firmware hex files [skip ci]

Merge pull request #48 from BenGardiner/try_mode_build_things

gsusb is in variants now; continue on errors with firmware upload on main

ci: update firmware hex files [skip ci]

Merge pull request #47 from BenGardiner/update-variant-building

collect and commit the firmware variants on main and release

complete the build macro coverage by adding a couple more variants

fix kwp build by setting smaller buffer

add a gs_usb + bitbang variant