Create CI workflow for Command Station

.github/workflows/main.yml

@@ -0,0 +1,17 @@
+name: CI
+
+on: [push]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: Install Python Wheel
+      run: pip install wheel
+    - name: Install PlatformIO Core
+      run: pip install -U https://github.com/platformio/platformio/archive/v4.2.1.zip
+    - name: Compile Command Station (AVR)
+      run: python -m platformio run