Bump actions/cache action to v6

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
actions/cache	action	major	v5 → v6

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Release Notes

actions/cache (actions/cache)

v6.1.0

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What's Changed

• Bump @​actions/cache to v6.1.0 - handle read-only cache access by @​jasongin in #​1768

Full Changelog: actions/cache@v6...v6.1.0

v6.0.0

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What's Changed

• Update packages, migrate to ESM by @​Samirat in #​1760

Full Changelog: actions/cache@v5...v6.0.0

v6

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