Automate updating the pack to new snapshots

[MMK21Hub]

Snapshots are released frequently, making it hard to keep up when updating the pack. Parts of this process could do with some more/smarter automation.

The general process of creating a variant for a just-released snapshot:

1. If necessary, update targetVersions in main.ts to ensure the latest snapshot is included.
2. Perform a test build of the pack: node dist/main.js. Check for JS errors. Check for validation warnings.
3. Often, a bug from the pack has been fixed in the just-released snapshot. The build tool will produce a warning at step 2. To remedy the issue, add a version constraint to the fix in fixes.ts. This prevents the fix from being emitted for versions that don't suffer from the bug.
4. Once all the warnings/errors have been dealt with, the new variant can be created and published.
5. Build the pack with the correct version brand, e.g. node dist/main.js v2.18.
6. Add the new variant to Modrinth: node dist/publisher/main.js. Check that the changelog is correct for the current version (e.g. v2.18).
7. Upload the new variant .zip files to the GitHub release, e.g. https://github.com/MMK21Hub/Capitalisation-Fixes/releases/tag/v2.18
8. Then, update the README
9. Update the version name and download link in the Download section. Check that the link is valid.
10. Update the table in the Statistics section. Check the stats with node dist/main.js --stats --latest-snapshot, then update the version name in the first column.