Mpltoolbox

What's Changed
* Improve callback mechanism and refactor internals by nvaytet in https://github.com/scipp/mpltoolbox/pull/16
* Require mpl>=3.6 by nvaytet in https://github.com/scipp/mpltoolbox/pull/17
* Remove dependency on get_corners and remove lower version bound for mpl by nvaytet in https://github.com/scipp/mpltoolbox/pull/18


**Full Changelog**: https://github.com/scipp/mpltoolbox/compare/0.2.0...0.3.0

What's Changed
* Add vertical and horizontal spans by nvaytet in https://github.com/scipp/mpltoolbox/pull/15


**Full Changelog**: https://github.com/scipp/mpltoolbox/compare/0.1.3...0.2.0

What's Changed
* Improve release event also in patches (after they were updated in lines) by nvaytet in https://github.com/scipp/mpltoolbox/pull/14


**Full Changelog**: https://github.com/scipp/mpltoolbox/compare/0.1.2...0.1.3

What's Changed
* Fix bad event kind in drag release event by nvaytet in https://github.com/scipp/mpltoolbox/pull/13


**Full Changelog**: https://github.com/scipp/mpltoolbox/compare/0.1.1...0.1.2

What's Changed
* Make dict for event content in line release events by nvaytet in https://github.com/scipp/mpltoolbox/pull/12


**Full Changelog**: https://github.com/scipp/mpltoolbox/compare/0.1...0.1.1

What's Changed
* Callbacks notebook by nvaytet in https://github.com/scipp/mpltoolbox/pull/11


**Full Changelog**: https://github.com/scipp/mpltoolbox/compare/0.0.8...0.1