Upgrade remaining GitHub Actions to Node 20

[tofumatt]

Bug Description

Some GitHub actions (eg. actions/cache) are still using older versions of the Node runtime and should be upgraded to newer versions that use supported versions of Node.

See: https://github.com/google/site-kit-wp/issues/8428#issuecomment-2176499826

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Do not alter or remove anything below. The following sections will be managed by moderators only.

Acceptance criteria

• All actions/cache actions should not warn about outdated Node versions (eg. should use Node 20)
• All actions/download-artifact actions should not warn about outdated Node versions (eg. should use Node 20)
• All actions/upload-artifact actions should not warn about outdated Node versions (eg. should use Node 20)
• All google-github-actions/upload-cloud-storage actions should not warn about outdated Node versions (eg. should use Node 20)

Implementation Brief

• [ ] Update cache actions to v4 at:
  • [ ] https://github.com/google/site-kit-wp/blob/e46b360a0f353f0d41e263e6c4989b0f5e4433f2/.github/workflows/e2e-tests.yml#L119
  • [ ] https://github.com/google/site-kit-wp/blob/e46b360a0f353f0d41e263e6c4989b0f5e4433f2/.github/workflows/php-lint-tests.yml#L59
  • [ ] https://github.com/google/site-kit-wp/blob/e46b360a0f353f0d41e263e6c4989b0f5e4433f2/.github/workflows/php-lint-tests.yml#L127
  • [ ] https://github.com/google/site-kit-wp/blob/e46b360a0f353f0d41e263e6c4989b0f5e4433f2/.github/workflows/zips.yml#L98
• [ ] Update Download Artifact actions to v4 at:
  • [ ] https://github.com/google/site-kit-wp/blob/e46b360a0f353f0d41e263e6c4989b0f5e4433f2/.github/workflows/storybook.yml#L87
  • [ ] https://github.com/google/site-kit-wp/blob/e46b360a0f353f0d41e263e6c4989b0f5e4433f2/.github/workflows/storybook.yml#L153
  • [ ] https://github.com/google/site-kit-wp/blob/e46b360a0f353f0d41e263e6c4989b0f5e4433f2/.github/workflows/zips.yml#L138
  • [ ] https://github.com/google/site-kit-wp/blob/e46b360a0f353f0d41e263e6c4989b0f5e4433f2/.github/workflows/zips.yml#L233
• [ ] Update Upload Artifact actions to v4 at:
  • [ ] https://github.com/google/site-kit-wp/blob/e46b360a0f353f0d41e263e6c4989b0f5e4433f2/.github/workflows/e2e-tests.yml#L135
  • [ ] https://github.com/google/site-kit-wp/blob/e46b360a0f353f0d41e263e6c4989b0f5e4433f2/.github/workflows/storybook.yml#L72
  • [ ] https://github.com/google/site-kit-wp/blob/e46b360a0f353f0d41e263e6c4989b0f5e4433f2/.github/workflows/visual-regression.yml#L53
  • [ ] https://github.com/google/site-kit-wp/blob/e46b360a0f353f0d41e263e6c4989b0f5e4433f2/.github/workflows/zips.yml#L127
• [ ] Update Cloud Storage actions to v2 at:
  • [ ] https://github.com/google/site-kit-wp/blob/e46b360a0f353f0d41e263e6c4989b0f5e4433f2/.github/workflows/zips.yml#L146

Test Coverage

• All tests should continue to pass.

QA Brief

• No explicit QA is needed; as long as GitHub Actions still run successfully all is good 👍🏻

Changelog entry

• N/A

[eugene-manuilov]

IB ✔️

[tofumatt]

Moving directly to Approval since no QA is needed here.