install platform to fix setup error

Author: Jason2866

.github/workflows/example.yml

@@ -26,6 +26,7 @@ jobs:
           python -m pip install --upgrade pip
           pip install wheel
           pip install -U https://github.com/Jason2866/platformio-core/archive/refs/tags/v6.1.16+free.zip
+          pio pkg install --global --platform https://github.com/Jason2866/platform-espressif32.git#idf_installer
       - name: Build example
         run: |
           pio run