CI: More fixes and refactoring

[microdev1]

This PR contains the following changes:

• Split atmel-samd instead of raspberrypi: This more evenly distributes the number boards across matrix jobs.
• Refactor and simplify fetching port deps: Now port specific stuff can be placed in .github/actions/deps/ports/....
• Fix for empty exclude commit: Use github.event.pull_request.head.sha instead of github.event.after which can be empty.

[tannewt]

Would you mind just splitting out every port? I split nrf out in #7497 because I needed to install nrfutil for it. See that PR for some renaming too.

[microdev1]

Would you mind just splitting out every port?

I took a look at the nrfutil changes and this pr simplifies it.

The port specific configuration steps/dependencies for nrf can go in:

# .github/actions/deps/ports/nrf/action.yml

name: Fetch nrf port deps

runs:
  using: composite
  steps:
    - name: Get nrfutil 7+
      run: |
        wget https://developer.nordicsemi.com/.pc-tools/nrfutil/x64-linux/nrfutil
        chmod +x nrfutil
        ./nrfutil install nrf5sdk-tools
        mkdir -p $HOME/.local/bin
        mv nrfutil $HOME/.local/bin
        echo "$HOME/.local/bin" >> $GITHUB_PATH
      shell: bash
    - name: Print nrfutil version
      run: nrfutil -V
      shell: bash

Then the following conditional step can be added in:

# .github/actions/deps/ports/action.yml

- name: Set up nrf port
  if: steps.board-to-port.outputs.port == 'nrf'
  uses: ./.github/actions/deps/ports/nrf

[jepler]

It would be unfortunate to switch to this tool as we have user/developers who build on arm64 linux platforms (e.g., rpi)...

[tannewt]

It would be unfortunate to switch to this tool as we have user/developers who build on arm64 linux platforms (e.g., rpi)...

Are you talking about nrfutil? If so, #7497 is a better place to discuss this.

[tannewt]

Would you mind just splitting out every port?

I took a look at the nrfutil changes and this pr simplifies it.

I agree it simplifies that part but I'd still like to split the matrix by port rather than architecture. That would be clearer than having a mix as you have now.

[tannewt]

Approving and merging. @microdev1 will follow up with rework to each port.