Add wheels to new python version 3.9 and 3.10

[BerndDoser]

Currently, pip wheels for python version 3.6, 3.7 and 3.8 are available (https://pypi.org/project/astro-pink/#files). Python 3.9 and 3.10 will be added and 3.6 and 3.7 will be removed (end-of-life, https://devguide.python.org/versions/).

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Estimated time: 8h Dependencies: #67