Fix CI

Author: mathieucarbou

.github/workflows/build.yml

@@ -66,7 +66,7 @@ jobs:
         run: |
           python -m pip install --upgrade pip
           pip install --upgrade platformio
-          pio run -e ${{ matrix.board }}
+          REF_NAME="${{ github.ref_name }}" pio run -e ${{ matrix.board }}
           cp .pio/build/${{ matrix.board }}/firmware.bin ./safeboot-${{ matrix.board }}.bin
 
       - name: Upload