v1 second pre-release

What's Changed

• use python 3.9 also by @ismael-mendoza in #308
• Multiband feature minor fix by @mpaillassa in #325
• remove group sampling by @ismael-mendoza in #327
• Cosmos multiband notebook by @mpaillassa in #320
• Cosmos tutorial documentation by @mpaillassa in #321
• interactive tutorial notebook by @ismael-mendoza in #328
• Fix error in nbval ignore by @ismael-mendoza in #329
• Fix SCARLET related issues by @thuiop in #323
• Dynamic version by @ismael-mendoza in #330

Full Changelog: 1.0.0a1...1.0.0a2