feat: adopt @actions/cache 6.2.0 (cache-mode skip + read-denied warning) - #1781

Description

Adopts @actions/cache 6.2.0 and rebuilds the vendored dist/ bundles. The new toolkit version adds two cache-mode security behaviors:

• ACTIONS_CACHE_MODE skip: when the runner sets ACTIONS_CACHE_MODE, the action skips operations the effective mode does not permit. Restore is skipped for none and write-only; save is skipped for none and read. Each skip emits a single non-fatal info line and returns a cache miss on restore or a no-op on save. It never throws.
• Read/write denied warnings: when the cache service denies an operation because the token has no readable or writable scopes, the action surfaces a clear warning instead of a generic error, and continues without failing the run.

Motivation and Context

The cache service can restrict what a job's token is allowed to do (read, write, both, or neither). Previously a denied read or write surfaced as an opaque error. These changes make the client honor the mode up front and report policy denials clearly.

Regression safety: when ACTIONS_CACHE_MODE is unset or set to an unrecognized value, behavior is identical to today. The skip logic only triggers on the explicit restrictive values.

Note on activation: the client-side skip depends on the runner exporting ACTIONS_CACHE_MODE, and the denial warnings depend on the cache service returning the corresponding policy responses. Until those roll out, this bump is behavior-preserving.

Toolkit change: actions/toolkit#2447 (published as @actions/cache 6.2.0).

How Has This Been Tested?

• Full @actions/cache unit suite passing in the toolkit repo (tsc, jest, prettier, eslint clean).
• End-to-end validation on hosted runners using a test build of this action pinned to the unreleased toolkit code:
  • Env-driven matrix over none, read, write, write-only, unknown, and unset confirmed the expected skip or proceed outcome for both restore and save, with exactly one info line per skip and no failures.
  • With cache-mode enforcement enabled server-side, restore under a read-denied token returned the read-denied policy response and the action degraded to a warning plus cache miss; save under a write-denied token returned the write-denied policy response and degraded to a warning. Allowed and unset modes cached and restored normally.

Types of changes

• New feature (non-breaking change which adds functionality)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.