This makes sure the library version works with the server version.

Ideally we'd also want to check the version so we can error out if a too
old keycloak server is on the other side, but I don't see any public API changes
that would allow us to know if the library is too old.

Fixes #32

See #32

I couldn't find any breaking changes affecting us

We couldn't do this until now because we referenced them by a relative path with npm.
But now that we reference them by name and yarn handles the linking we can
specify them as normal dependencies.

They are not published yet

Fixed upstream: https://github.com/select2/select2/issues/5682

This way we don't have to mirror the directory structure in packages
which vendor this package.

No longer needed