chore(deps): update actions/setup-node action to v6

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
actions/setup-node	action	major	v4 -> v6

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Release Notes

actions/setup-node (actions/setup-node)

v6

Compare Source

v5

Compare Source

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Configuration

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🚦 Automerge: Disabled by config. Please merge this manually once you are satisfied.

♻ Rebasing: Whenever PR is behind base branch, or you tick the rebase/retry checkbox.

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• If you want to rebase/retry this PR, check this box

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This PR was generated by Mend Renovate. View the repository job log.

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Note

Replaces actions/setup-node@v4 with @v6 across CI, release, and manual workflows.

• GitHub Actions workflows:
  • Update actions/setup-node from @v4 to @v6 across all workflows in /.github/workflows (build/test, release pipelines, and manual publish/docs jobs).

^{Written by Cursor Bugbot for commit 60b510e. This will update automatically on new commits. Configure here.}

[github-actions]

@launchdarkly/browser size report
This is the brotli compressed size of the ESM build.
Compressed size: 169118 bytes
Compressed size limit: 200000
Uncompressed size: 789399 bytes

[github-actions]

@launchdarkly/js-sdk-common size report
This is the brotli compressed size of the ESM build.
Compressed size: 24988 bytes
Compressed size limit: 26000
Uncompressed size: 122411 bytes

[github-actions]

@launchdarkly/js-client-sdk-common size report
This is the brotli compressed size of the ESM build.
Compressed size: 17636 bytes
Compressed size limit: 20000
Uncompressed size: 90259 bytes

[github-actions]

@launchdarkly/js-client-sdk size report
This is the brotli compressed size of the ESM build.
Compressed size: 21721 bytes
Compressed size limit: 25000
Uncompressed size: 74698 bytes

[jsonbailey]

I created a PR to have renovate use digests instead of tags. We may want to review that before deciding if we want to merge this #955

[cursor]

Bug: Caching lost: actions/setup-node v6 drops Yarn caching

Upgrading to actions/setup-node@v6 removes automatic caching for Yarn. In v5, automatic caching was enabled for yarn/pnpm/npm when a packageManager field was present in package.json. In v6, automatic caching is limited to npm only. Since this repository uses Yarn 3.4.1 (as specified in package.json) and this workflow doesn't explicitly set cache: 'yarn', the workflow will lose automatic dependency caching, resulting in slower CI builds. The same issue affects all other workflow files in this PR that don't explicitly specify the cache parameter.