Use custom matrix job names in sketch compilation CI job

The "Compile Examples" GitHub Actions workflow generates a matrix job for each board. The default job name is generated
from the job's matrix object. This contains the complete board data, which results in a long and somewhat cryptic job
name that can make the workflow run more difficult to interpret.

The only necessary information is the FQBN. A custom job name allows for only using this information in the job name.

Author: per1234

.github/workflows/compile-examples.yml

@@ -19,6 +19,7 @@ on:
 
 jobs:
   build:
+    name: ${{ matrix.board.fqbn }}
     runs-on: ubuntu-latest
 
     env: