Update package name to lowercase in setup.py to match binary distribution format that is required on PyPi (#1528)

Author: AgnieszkaZaba

setup.py

@@ -21,7 +21,7 @@ def get_long_description():
 _32bit = platform.architecture()[0] == "32bit"
 
 setup(
-    name="PySDM",
+    name="pysdm",
     description="Pythonic particle-based (super-droplet) warm-rain/aqueous-chemistry"
     " cloud microphysics package with box, parcel & 1D/2D prescribed-flow"
     " examples in Python, Julia and Matlab",