Continuous integration with GitHub actions

I was trying to implement CI to ensure the component compiles for the various versions of ESP-IDF.

The problem is that the project is not set up in a way that allows for this: ESP-IDF components should be in a subfolder (commonly main/, but it could also be M5GFX/). Without this, any attempt to compile the component with idf.py build leads to this error:

Called idf_component_register from a non-component directory.

Reference build: https://github.com/KenVanHoeylandt/M5GFX/actions/runs/8222729252/job/22484559726

.github/workflows/build.yml example:

name: Build
on: [push]
jobs:
  build-esp-idf-4.4:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout repo
        uses: actions/checkout@v2
        with:
          submodules: recursive
      - name: build
        uses: espressif/esp-idf-ci-action@main
        with:
          esp_idf_version: v4.4
          target: esp32

To allow for idf.py build to work independently in this project, these steps are required:

[ ] Add a subfolder for this component (main/ or M5GFX/), move relevant files into this folder and add a CMakeLists.txt
[ ] Add include($ENV{IDF_PATH}/tools/cmake/project.cmake) to the root CMakeLists.txt

Considering that moving source files has a big impact on your currently unmerged branches, I figured I'd open this issue to discuss the proposed changes.

m5stack / M5GFX

Continuous integration with GitHub actions #85