truggles/EIA_Cleaned_Hourly_Electricity_Demand_Data: Annual update to 5 full years of clean data

The cleaned data have been updated since publication of the methods paper (early 2020 https://doi.org/10.1038/s41597-020-0483-x, see citation below) discussed throughout this repository. The most current cleaned data can be found in data/release_2020_Oct/ and corresponds to 5 full years of cleaned data spanning from 2 July 2015 through 1 July 2020 and follow the methods discussed in the paper exactly. Additionally, we have modified the method to incorporate subregion level data for the balancing authorities that provide this and provide 2 full years of cleaned data spanning 1 October 2018 through 30 September 2020 in the data/release_2020_Oct_include_subregions/ directory. Details of both updates can be found in README files at the paths above.