v2.0.3

Summary:
This adds a fair bit of functionality while refactoring some functions and modules to better fit the current code structure. Added new HAMTIDE model as an option using the FES file standard (thanks @martin-rdz for the suggestion!). Added capabilities to predict solid Earth tides following IERS conventions. Added "one-liner" functions to predict long-period equilibrium tides (LPET), load pole tides (LPT) and ocean pole tides (OPT) and solid Earth tides (SET) (thanks Jeremy Harbeck for the suggestion!).

Itemized Changes:

• feat: add basic variable typing to function inputs (#174)
• feat: added "one-liners" for LPET, LPT and OPT (#176)
• feat: added option to change IERS mean or secular pole convention (#176)
• feat: added 2018 IERS secular pole convention (#176)
• feat: set ellipsoid name and output units as constants attributes (#176)
• feat: add 'HAMTIDE11' model to address #179 (#180)
• feat: adding work for computing solid earth tides (#186)
• feat: add solid Earth tide (SET) correction program for files (#186)
• feat: add function for phase angles (#186)
• test: add solid Earth tide (SET) checks vs IERS and ICESat-2 (#186)
• refactor: renamed coordinate reference system conversion functions (#174)
• refactor: mapping notebooks for matplotlib 3.5 (#182)
• fix: setting directories for FES currents within model class (#182)
• fix: check if datetime before converting to seconds (#186)
• fix: copy inputs in cartesian conversions to not modify original arrays (#186)
• docs: remove deprecated .rst files (#174)
• docs: update documentation to denote new solid Earth tide (SET) functionality (#186)

Full Changelog: 2.0.2...2.0.3