Create workflow

* Native test
* Cross binaries production

.github/workflows/main.yml

@@ -0,0 +1,33 @@
+name: PlatformIO CI
+
+on: [push]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/cache@v3
+        with:
+          path: |
+            ~/.cache/pip
+            ~/.platformio/.cache
+          key: ${{ runner.os }}-pio
+      - uses: actions/setup-python@v4
+        with:
+          python-version: '3.9'
+      - name: Install PlatformIO Core
+        run: pip install --upgrade platformio
+
+      - name: Test project in native environment
+        run: pio test -e native
+
+      - name: Build console application
+        run: pio run -e native
+
+      - name: Build 'target' cross application
+        run: pio run -e target
+
+      - name: Build 'gun' cross application
+        run: pio run -e gun