Update GitHub actions using Node.js 16

[o-l-a-v]

GitHub actions is deprecating Node.js 16. Starting in May, GitHub will force actions to use Node.js 20.

• 2023-09-22 "GitHub Actions: Transitioning from Node 16 to Node 20": https://github.blog/changelog/2023-09-22-github-actions-transitioning-from-node-16-to-node-20/
• 2024-03-07 "GitHub Actions; All Actions will run on Node20 instead of Node16 by default": https://github.blog/changelog/2024-03-07-github-actions-all-actions-will-run-on-node20-instead-of-node16-by-default/