javascript: add node v20 to default known versions

[kevinobruno]

Add nodejs v20 to default known versions as its the current LTS https://endoflife.date/nodejs.

I naively tried to bump the default_version to v20.11.1, but a lot of tests fails for reasons I'm still not sure.

Adding the v20 to default_known_versions at least reduces the pants.toml file when anyone wants to use the v20 as only the version option of the nodejs subsystem will need to be specified.

I plan to explore more about the upgrade from node v16 to v20 and putting a PR to change the default_version to v20 soon.

Related to https://github.com/pantsbuild/pants/issues/19131

[kaos]

Thanks for looking into this!

I think we want to upgrade default_known_versions at the same time as default_version. If tests starts failing, it doesn't feel like we want to say we support v20 yet.. so adding that version to default_known_versions kind of gives the wrong impression then.

[huonw]

Heya @tobni, the test failures here looks like something you might have insight into. What do you think?