EIA API requires https

[leachandrew]

As of Feb 22, EIA API requires https authentication:

Since pdfetch_EIA uses http, it won't work:
url <- paste0("http://api.eia.gov/series/?series_id=", id, "&api_key=", api_key)

Here's the output using the package example call:

pdfetch_EIA(c("ELEC.GEN.ALL-AK-99.A","ELEC.GEN.ALL-AK-99.Q"), KEY)
NULL

Warning messages:
1: In pdfetch_EIA(c("ELEC.GEN.ALL-AK-99.A", "ELEC.GEN.ALL-AK-99.Q"),  :
  Invalid series code ELEC.GEN.ALL-AK-99.A
2: In pdfetch_EIA(c("ELEC.GEN.ALL-AK-99.A", "ELEC.GEN.ALL-AK-99.Q"),  :
  Invalid series code ELEC.GEN.ALL-AK-99.Q