Megaradrp

Contains fix for bug 302

**Full Changelog**: https://github.com/guaix-ucm/megaradrp/compare/v0.12.0...v0.12.1

* Drop Python 3.6, working up to Python 3.10
* Fix WCS is rotated in the wrong direction (298)
* Fix problem with matplotlib < 3.3
* New parameter `smoothing_knots` in the master sensitivity recipe (300)

* Fixed a problem with contouring in visualization (296).
* Improved matching of traces

* Support `astropy` 4.0