Update EPA-EIA crosswalk to use 2021 data

[e-belfer]

WIP: Update to use 2021 data. See issue here.

Still to do:

• Configure fork to sync w/ upstream repo automatically
• Add documentation to repo readme
• Set up basic pre-commit configurations for branch?

[e-belfer]

Right now the existing code is tripped up by an error in the encoding of the CAMD data, with one character improperly converted to UTF-8. Running:

response <-
  GET(str_glue(
    "https://api.epa.gov/FACT/1.0/facilities?api_key={api_key}"
  ))

results in the error: Error in substring(u, so, so + ml - 1L) : invalid multibyte string, element 1
I fix this by using another library to read in the json, which also requires slight retooling of the transform of this data

[zschira]

Looks good to me! I'm going to go ahead and merge this so I can get it all archived. Also, I don't think we need to worry about pre-commit hooks at this point. If we end up doing more active development here it might be nice, but I think it's fine for now