2.9.44.1

What's Changed

This is a patch release on the 2.9 track. Most significant change is the added support for nested assumes expressions in #940.

• Cleanup release process by @cderici in #921
• [JUJU-4488] Add licence headers to source files by @cderici in #933
• Parse nested assumes expressions by @cderici in #940
• Release 2.9.44.1 notes by @cderici in #944

Full Changelog: 2.9.44.0...2.9.44.1