Upgrade the `download-artifact` from v3 to v4

[iamdharmesh]

Description of the Change

The PR proposes upgrading the download-artifact to v4. This upgrade is related to the upgrade of upload-artifact to v4 in PR https://github.com/10up/action-wordpress-plugin-build-zip/pull/3. Version 4 contains breaking changes, and this PR ensures that everything keeps working after the build zip action updates the upload-artifact to v4.

[!NOTE] Please merge this PR after the action https://github.com/marketplace/actions/wordpress-plugin-build-zip gets released.

How to test the Change

Please ensure that the E2E test action runs successfully after the release of the action available at https://github.com/marketplace/actions/wordpress-plugin-build-zip.

Changelog Entry

Changed - Upgrade the download-artifact from v3 to v4

Credits

Props @iamdharmesh

Checklist:

• [x] I have read the CONTRIBUTING document.
• [x] 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 added tests to cover my change.
• [ ] All new and existing tests passed.