Upgrade the workflows in GitHub Actions to use Node.js v20

[eason9487]

Changes proposed in this Pull Request:

This PR upgrades the workflows in GitHub Actions to use Node.js v20.

Checks:

• Does your code follow the WordPress coding standards?
• Have you written new tests for your changes, as applicable?
• Have you successfully run tests with your changes locally?
• Have you checked to ensure there aren't other open Pull Requests for the same update/change?

Detailed test instructions:

1. View the Checks tab to check if all checks have passed and if there are no longer deprecated warnings about Node.js <= 16
2. View the E2E Tests result that is not listed in the Checks tab
3. The rest of workflows that can't be viewed in this PR have basically been verified during development, if one wants to view them, please find the corresponding development RP in Upgrade to Node.js v20 grow#108

Changelog entry

[puntope]

Thanks @eason9487

Here I miss the Build WF (similar to https://github.com/woocommerce/automatewoo-birthdays/pull/139#issuecomment-2116653649)

and the Branch label assignation as reported here https://github.com/woocommerce/automatewoo-birthdays/pull/139#issuecomment-2116662381

[eason9487]

Hi @puntope, thanks for the review.

Here I miss the Build WF (similar to woocommerce/automatewoo-birthdays#139 (comment))

and the Branch label assignation as reported here woocommerce/automatewoo-birthdays#139 (comment)

Please refer to https://github.com/woocommerce/automatewoo-birthdays/pull/139#issuecomment-2116918286