Bump @actions/cache to 5.1.0, log cache write denied

[jasongin]

Description:

• Bump @actions/cache to v5.1.0 to pick up actions/toolkit#2435 Handle cache write error due to read-only token
• Update generated JavaScript files under dist
• Update license file for dependencies
• Bump minor version in package.json from 6.4.0 to 6.5.0

Check list:

• Mark if documentation changes are required.
• Mark if tests were added or updated to cover the changes.

[Copilot]

Pull request overview

This PR updates setup-node’s caching behavior to align with @actions/cache@5.1.0, including improved handling/logging when cache writes are denied (for example, read-only tokens on fork PRs). It also bumps the action’s minor version and refreshes generated artifacts and dependency licensing metadata.

Changes:

• Bump @actions/cache dependency to ^5.1.0 and update action version to 6.5.0.
• Add a debug log when saveCache returns -1 (cache not saved) and update tests accordingly.
• Regenerate dist bundles and update the cached dependency license file.

Show a summary per file

File	Description
src/cache-save.ts	Adds a debug log when @actions/cache.saveCache indicates the cache was not saved (-1).
__tests__/cache-save.test.ts	Updates test expectations to validate the new debug log behavior.
package.json	Bumps action version to 6.5.0 and updates @actions/cache to ^5.1.0.
package-lock.json	Locks @actions/cache to 5.1.0 and updates the root version metadata.
dist/setup/index.js	Regenerated bundle reflecting the updated @actions/cache behavior.
dist/cache-save/index.js	Regenerated bundle reflecting the new cache-write-denied handling and the new debug log.
.licenses/npm/@actions/cache.dep.yml	Updates recorded dependency version for @actions/cache to 5.1.0.

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• Files reviewed: 4/7 changed files
• Comments generated: 1