update CITATION.cff: license, longer title, version

Author: bast

CITATION.cff

@@ -1,9 +1,10 @@
-cff-version: 1.0.3
-message: If you use numgrid, please cite it as below.
+cff-version: 1.1.0
+message: If you use Numgrid, please cite it as below.
 authors:
   - family-names: Bast
     given-names: Radovan
-title: numgrid
+title: "Numgrid: Numerical integration grid for molecules."
 version: 1.1.0
+license: MPL-2.0
 doi: 10.5281/zenodo.2659208
 date-released: 2019-05-03