Adding a Julia version

To update the Julia versions that Juliaup knows about, run this workflow. The workflow automatically pulls known Julia versions from the official versions.json, and then does two things:

1. Opens a PR on this repository here that integrates the changes into the Juliaup binaries. Once that PR is merged and a new Juliaup build is published, users will get a juliaup build that has the new version info embedded in the binary. Typically getting a new build out to users can take a while, so this is potentially a slow process.
2. It pushes new version info files to the S3 bucket for Juliaup. Juliaup binaries regularly check that S3 bucket and download a version db from there if there is one available that is newer than the info that is embedded in the binaries itself. This is the fast path to push out new Julia versions to Juliaup clients, typically only a few minutes.

At some point we will trigger runs of this workflow to happen automatically whenever versions.json is updated.

To change which version Juliaup considers the LTS version, update the first lines in this script.