Version 2.44.1
- This is a brown paper bag release!  Apologies for the bugs:
- Fix #324 - Don't panic if trying to render a non-empty SVG with no
  elements (Paolo Borelli).
- Fix #325 - All the elements were being leaked at the toplevel.
- Fix #326 - Fix COMPILING.md - librsvg 2.44 does not build on Ubuntu
  18.04 because it has a rust version that is too old.