Updated release workflow

[sebjulliand]

Changes

This PR enhances the release workflow by automating the version number change. This allows to make a new release without the need to create a PR to bump the version number in package.json.

It does the following:

1. Updates the version to match the release tag's
2. Packages once using vsce (through npx)
3. Publishes the package on the marketplace and openvsx
4. Attaches the vsix as a release asset
5. Commits the version number change, moves the release tags to this commit and pushes it all
6. Updates the version with a new prerelease version, bearing the -dev suffix
7. Commits and pushes the version update

It also uses Node 18 for building.

Checklist

• have tested my change (on another repo)

[worksofliam]

Looks ok to me. One way to find out if it works is by making a release, I guess? :)