remove fixation of matplotlib

[Reimar Bauer]

Sometime ago we fixated matplotlib to 3.0.2 recent version is 3.2.2
https://bitbucket.org/wxmetvis/mss/issues/408/fixate-matplotlib-to-302

We should try this version and feed our issues to the core code if they still exists.

‌

[Reimar Bauer]

Merged in ReimarBauer/mss/new_fixations (pull request #875)

changed fixations of some modules, fixes #580, #558

→ <<cset a8960c49ed45>>