Updated .zenodo.json. Added CITATION file. Added hint regarding citation to README.rst.

Signed-off-by: Daniel Scheffler <danschef@gfz-potsdam.de>
3 jobs for v0.11.7 in 48 minutes and 59 seconds (queued for 64 minutes and 40 seconds)
latest
Status Name Job ID Coverage
  Test
passed test_enpt #25896

00:48:02

88.0%
passed test_styles #25897

00:00:25

 
  Deploy
passed deploy_pypi #25898

00:00:31