Update Node.js version to 18 in app.Dockerfile

[savioribeiro]

This update changes the Node.js version in app.Dockerfile from 16 to 18 to resolve compatibility issues with [email protected].

[knadh]

Could you please confirm that the switch to Node 18 doesn't break any JS dependencies? Also, I'm unsure what the issue with eslint-define-config is.

[savioribeiro]

I'm not sure if any dependencies broke with node 18, although I was able to run it today using version 16 and 18. Anyway, I managed to recover the log with the warnings and errors I initially had:

warning Resolution field "[email protected]" is incompatible with requested version "jackspeak@^3.1.2"
[2/4] Fetching packages...
warning [email protected]: The engine "pnpm" appears to be invalid.
error [email protected]: The engine "node" is incompatible with this module. Expected version ">=18.0.0". Got "16.20.2"
warning [email protected]: The engine "pnpm" appears to be invalid.
error Found incompatible module.
info Visit https://yarnpkg.com/en/docs/cli/install for documentation about this command.
make: *** [Makefile:37: frontend/node_modules] Error 1