Adapt npm-on-release workflow for 3.x

[Kocal]

For https://github.com/symfony/ux/blob/2.x/.github/workflows/release-on-npm.yaml

• The 2.x branch from git push origin 2.x should be computed given the tag, e.g. v2.*.* should gives 2.x and v3.*.* should gives 3.x
• The tag pattern v3.*.* must be added to the tags list