Release of libvirt 6.4.0
Release of libvirt 6.4.0

* docs/news.xml: update for release date

Signed-off-by: Daniel Veillard <8c3f1b821d9adf233f787f1527ecaa1537ea24a2@redhat.com>

olafhering/libvirt,jfehlig/libvirt,zippy2/libvirt,olafhering/libvirt,jfehlig/libvirt,libvirt/libvirt,libvirt/libvirt,jardasgit/libvirt,crobinso/libvirt,jardasgit/libvirt,libvirt/libvirt,crobinso/libvirt,crobinso/libvirt,zippy2/libvirt,jfehlig/libvirt,zippy2/libvirt,nertpinx/libvirt,jardasgit/libvirt,libvirt/libvirt,olafhering/libvirt,jardasgit/libvirt,jardasgit/libvirt,jfehlig/libvirt,nertpinx/libvirt,olafhering/libvirt,nertpinx/libvirt,nertpinx/libvirt,crobinso/libvirt,nertpinx/libvirt,zippy2/libvirt