feat: upgrade from node 16 to 20

[Multimo]

#185

Upgrades node to use v20 and also upgrades some of the internal actions to v4 so that they also use v20.

Not quite sure how to test this so any direction here would be helpful :)

[cclauss]

You can automate most of these changes by using GitHub's Dependabot.

• Keep GitHub Actions up to date with GitHub's Dependabot #188

[marcinlesek]

Thank you @Multimo 🎉

@ryon @themightychris can you folks please take a look on that? Now all Actions shows warning about this deprecation. 🙏🏻

[till]

Can haz merge? 😄

[jmealo]

@till: I need to check with @themightychris that the hologit part works with Node 20, if so we should be good to merge this

[jmealo]

@till: @cclauss: I checked with @themightychris, the changes you made are correct, however, we need to push an update for hologit that supports Node 20 for them to work. I can't commit to when this would happen but he's aware of the issue. Once hologit supports Node 20, we should be able to merge this.

[till]

Thank you very much!