* workflow update

.github/workflows/compile_esp8266.yml

@@ -1,12 +1,18 @@
 name: PlatformIO ESP82266
 
-on: [push]
+on:
+  push:
+    branches: main
+    paths-ignore:
+    - '**.md' # Do no build on *.md changes
 jobs:
   build:
     runs-on: ubuntu-latest
 
     steps:
     - uses: actions/checkout@v3
+      with:
+        ref: main
     - name: Cache pip
       uses: actions/cache@v3
       with:
@@ -27,5 +33,8 @@ jobs:
         pip install --upgrade platformio
     - name: Run PlatformIO
       run: |
-        pio project config -d tools/esp8266
-        pio run -e d1_mini
+        pio run -d tools/esp8266
+    - uses: actions/upload-artifact@v3
+        with:
+          name: firmware
+          path: ./build_output