Pin sketch-build Arduino CLI to 1.0.3

[Copilot]

The sketch-build workflow started failing on the GitHub-hosted runner after Arduino CLI drifted from the version this job had previously been working with. This change pins the cloud runner job back to the known-good 1.0.3 release in .github/workflows/checkSketches.yml.

• Scope

  • Update only the arduino-cli_compile_all job in the sketch build workflow.
  • Leave the self-hosted job and all other workflow behavior unchanged.

• Workflow change

  • Add an explicit version pin to the existing arduino/setup-arduino-cli@v2 step.
  • Preserve the existing install path comment that already points to 1.0.3 as the expected hosted-runner CLI version.

• Result

  • Removes reliance on whatever Arduino CLI version the action resolves by default.
  • Restores deterministic CLI selection for the cloud sketch compilation path.

- name: Install Arduino CLI
  uses: arduino/setup-arduino-cli@v2
  with:
    version: 1.0.3