getRad 0.2.0

• New function get_weather_radars() retrieves metadata for OPERA weather radars (#15, #54).
• New function get_vpts() downloads vertical profile time series from the Aloft bucket and RMI (#10, #53).
• New function get_vpts_coverage() fetches an overview table of the files available on the Aloft bucket (#10) and RMI.
• get_pvol() now downloads polar volumes from NOAA (United States) (#55).
• Add Cecilia Nilsson and Alexander Tedeschi as contributors.