Incorporate the functionalities enabled by pandas 2.x (to be released in February), including:

• resample() (bring to API level with paleo semantics like .resample('5 ka'))
• pyleo.Series.select() (new API method replacing slice(), emulating Xarray's .sel() )
• create MultipleSeries object from pandas DataFrame columns (MS_from_DataFrame(df, cols = ...) )
• time unit conversions
• align() should replace common_time()
• to_xarray()
• to_csv()
• to_json()
• drop_duplicates()
• head() and tail() (bring to API level)
• clean_ts will now use pd.Series.drop_na() and pd.Series.sort_index()