use the lora-relay board for CI builds

.github/workflows/main.yml

@@ -23,4 +23,4 @@ jobs:
         run: |
           pip install -U adafruit-nrfutil
       - name: Build
-        run: platformio run -e tbeam -e heltec -e nrf52840dk -e rak815
+        run: platformio run -e tbeam -e heltec -e lora-relay-v1