Ukis-pysat

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Added
^^^^^
- Added Landsat 8 Collection 2 support 173

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Deleted
^^^^^^^
- Removed data part 170

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Fixed
^^^^^
- Fixed bug in bandorder dn2toa

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Changed
^^^^^^^
- Adapt band schema of Sentinel-2 168

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Changed
^^^^^^^
- Adapt to new ESA Sentinel-2 processing baseline 165

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Changed
^^^^^^^
- Sentinel items closer to standards of stactools 155

Deleted
^^^^^
- removed own stac api client (pystac-client should be used from now on)
- deleted the StacApi reference in data.py