Use v1 ref of arduino/setup-protoc action

[per1234]

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• The PR has no duplicates (please search among the Pull Requests
  before creating one)
• The PR follows our contributing guidelines
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

• What kind of change does this PR introduce?

Bug fix.

• What is the current behavior?

CI workflows use the v1.0.0 ref of the arduino/setup-protoc action. This presents two issues:

• Because that version of the action is missing metadata for its repo-token input, an Unexpected input(s) 'repo-token', valid inputs are ['version'] warning is displayed in every workflow run summary, which could result in confusion for contributors.
• Pinning to a specific version results in either not benefiting from ongoing development, or the need to update the workflows on every release.

• What is the new behavior?

The v1 ref of the action is specified, which has two benefits:

• The "unexpected input" warning is no longer displayed in the workflow run summaries.
• The workflow will automatically use any minor or patch releases of the action, but will require manual updating in the event that breaking changes result in a major version release.
• Does this PR introduce a breaking change?

No.