ci(build): replace board matrix array with list
A multi-line list can be more merge friendly than a single-line array.
PR:
@@ -15,7 +15,11 @@ jobs:
runs-on: ubuntu-latest
strategy:
matrix:
- board: [proton_c, nice_nano, bluemicro840_v1, nrfmicro_13]
+ board:
+ - proton_c
+ - nice_nano
+ - bluemicro840_v1
+ - nrfmicro_13
shield:
- boardsource3x4
- corne_left
