sabre/xml 1.0.0 release

We just released sabre/xml 1.0.0

This version is identical to the earlier released 0.4.3. We figured it was good enough to be released as a true stable release, and the soon-to-be-released sabre/dav requires stable dependencies.

Upgrade sabre/xml by making sure your composer.json has ~1.0 as a version requirement, and then just run composer update.

Full changelog of this release can be found on Github.