chore(renovate): add internalChecksFilter strict to ruby setup group

[mensfeld]

Ensures Renovate waits until both ruby and ruby/setup-ruby have cleared the minimumReleaseAge window before creating the grouped PR, preventing partial dependency update PRs that fail CI.

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[Copilot]

Pull request overview

This PR updates Renovate configuration so the grouped Ruby setup updates wait for internal checks before opening, aligning with the configured minimumReleaseAge.

Changes:

• Adds internalChecksFilter: "strict" to the Ruby setup package rule.
• Keeps ruby/setup-ruby and ruby grouped together under the existing ruby setup group.

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