Lenscat

This minor release contains code changes allowing for much prettier plotting with dark mode.

This release, 0.1.3, fixes multiple bugs in 0.1.2 (which should not be used).

This minor release

- changes the underlying plotting from `healpy` to `astropy` and `ligo.skymap`
- switches to a new color scheme for plotting
- adds support for plotting in dark theme (by passing an option `dark_theme=True`)
- allow right ascension to be either in deg (default) or hms (by passing an option `RA_unit="deg"` or `RA_unit="hms"`)

There are two changes in this release:

- addition of `lenscat.utils.check_possible_duplicates()`
- new color scheme for `lenscat.utils.plot_catalog()`

This is a breaking release (in principle the major version should be advanced instead of the minor version but whatever). While the content of the catalog itself is unchanged, there is now a new class `Catalog` that we inherit from `astropy`'s `Table` class to support two features, namely searching and cross-matching.