Release 3.6.1 Add an alternative XML parsing API based on `quick-xml`, which is enabled through a new `quick-xml` cargo feature. This is because `serde-xml-rs` is unmaintained,. `serde-xml`-based `xml` API will eventually be dropped in favour of this. Including new API in a micro release cause this was intended to be part of 3.6.0. So it's sort of a fix.