install fails on windows-11-arm runner

[robtaylor]

   - name: Install MSYS2 dependencies
      uses: msys2/setup-msys2@v2
      if: contains(matrix.os, 'windows')
      with:
        update: false
        release: false
        cache: true
        install: |
          git
        pacboy: |
          toolchain

Fails with:

Run msys2/setup-msys2@v2
  with:
    update: false
    release: false
    cache: true
    install: autotools
  git
    pacboy: toolchain

  
  
    msystem: MINGW64
    path-type: minimal
    location: RUNNER_TEMP
    platform-check-severity: fatal
Restoring package cache...
  Cache restore for msys[2](https://github.com/ChipFlow/Xyce-build/actions/runs/15756778839/job/44413870974#step:5:2)-pkgs-upd:false-conf:d84f6[3](https://github.com/ChipFlow/Xyce-build/actions/runs/15756778839/job/44413870974#step:5:3)62, got undefined
  Cache restore for msys2-pkgs-upd:false-conf:d8[4](https://github.com/ChipFlow/Xyce-build/actions/runs/15756778839/job/44413870974#step:5:4)f6362, got undefined
Starting MSYS2 for the first time...
  C:\Windows\system32\cmd.exe /D /S /C C:\a\_temp\setup-msys2\msys2.cmd -c "'uname' '-a'"
  The system cannot find the path specified.
  Error: The process 'C:\Windows\system32\cmd.exe' failed with exit code 1

[mmuetzel]

I'm assuming you are using the runner image for Windows on ARM that is provided by GitHub. That doesn't come with a pre-installed MSYS2. So, you'll need to set release: true to install MSYS2 from scratch.

See also: actions/partner-runner-images#88

Also, you'd likely want to use toolchain:p (with the trailing :p) in the pacboy section of that step.