3.0.6

• #730: Switched all mysql tables to utf8mb4 character set, allowing you to
  use emoji in some tables where you couldn't before.
• #729: Not all calls to Sabre\DAV\Tree::getChildren() were properly cached.
• #734: Return 418 I'm a Teapot when generating a multistatus response that
  has resources with no returned properties.
• #740: Bugs in migrate20.php script.
• The zip release ships with sabre/vobject 3.4.8,
  sabre/http 4.1.0, sabre/event 2.0.2,
  sabre/uri 1.0.1 and sabre/xml 1.3.0.