Upgrade to Node.js 20

[thedavidchu]

It looks like GitHub is deprecating actions using Node.js 16.

I get the following warning in my build:

Node.js 16 actions are deprecated. Please update the following actions to use Node.js 20: BSFishy/meson-build@v1.0.3.
For more information see: https://github.blog/changelog/2023-09-22-github-actions-transitioning-from-node-16-to-node-20/.

[thedavidchu]

Alternatively, it looks like pip installing Meson is a work-around, so I will accept a wontfix.

Source: https://github.com/mesonbuild/meson/blob/master/docs/markdown/Continuous-Integration.md