start preparing build-runtime job

[girazoki]

Adds a CI job able to publish the runtime release on request, giving the previous tag name and the new one

[tmpolaczyk]

In the tests/ dir we don't commit package-lock.json, we commit the pnpm-lock.yaml created by pnpm. So maybe it is worth it to also use pnpm here?

[girazoki]

I can check it out

[girazoki]

I tried pnpm but failed. Will try in a future pr, for now I will leave yarn

[crystalin]

changing to use label instead of generic self-hosted will be easier for maintenance

[girazoki]

yes, we have an issue for that already. But will do a PR changing all those at once.