Github Actions using Node 12 are deprecated

[ADKaster]

We're using quite a few github actions, and it looks like the ones based on node12 will be removed sometime next year

https://github.blog/changelog/2022-09-22-github-actions-all-actions-will-begin-running-on-node16-instead-of-node12/

We should audit such actions and update them before the EOL date.

From the warnings for normal builds::

• [ ] actions/checkout
• [ ] actions/setup-python
• [ ] actions/cache
• [ ] actions/github-script (lintcommits)

From master-only jobs

• [ ] CodeQLv1 --> v2 (PVSStudio)
• [ ] JamesIves/github-pages-deploy-action (test262)
• [ ] actions/upload-artifact (test262)
• [ ] actions/setup-node (notify twitter)