Update characteristics using 2020 RECS v7 data

[afontani]

Pull Request Description

Companion PR: resstock-estimation PR #394

Updates RECS 2020 data from v5 to v7. There are some new EV variables to be leveraged by the ResStock/TEMPO project. I am not sure what V6 was as there is no documentation.

The only changes were small rounding differences in the last one or two decimal places.

Checklist

Not all may apply:

• [x] Tests (and test files) have been updated
• [x] Documentation has been updated
  • [x] If related to resstock-estimation, checklist includes data dictionary, source report, options saturation, options_lookup.
• [x] Changelog has been updated
• [ ] openstudio tasks.rb update_measures has been run
• [x] No unexpected regression test changes on CI (checked comparison artifacts)