v1.1.2

Summary:
Added ERA5-Land as a possible model for terrestrial water storage (TWS) change. Updates to the citations and references within the documentation.

Itemized Changes:

• feat: can mosaic Release-3 ATL15 granules into a single grid (#66)
• refactor: change constants class to datum (#67)
• fix: updated ssl context to fix deprecation error (#67)
• refactor: changed polar stereographic area function to scale_factors (#67)
• feat: updates for using downscaled Antarctic RACMO products (#67)
• feat: add ERA5-Land as TWS option (#68)
• feat: add spatial regress program for smoothed fields (#68)
• feat: output centered SMB in addition to cumulative GEMB (#68)
• fix: earth's density attribute (#68)
• fix: CMR search utility to replace deprecated scrolling (#68)
• docs: use sphinxcontrib-bibtex for citations (#68)
• feat: use bessel function for points within cutoff distance (#68)
• feat: add ERA5-Land download (#68)
• feat: add read functions for ERA5-Land (#68)
• feat: add ERA5-Land harmonics program (#68)
• feat: add ERA5-Land arctic and permafrost masks (#68)
• fix: turn set_auto_mask to False (#68)
• feat: take union of polygons for a permafrost type (#68)
• feat: added option to buffer polygons (#68)
• docs: add ERA5-Land pages (#68)
• docs: improve citations (#68)

Full Changelog: 1.1.1...1.1.2