Header names are not RFC 2616 (Field names are case-insensitive)

[jklein131]

As per: https://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html#sec4.2
This works:
curl -H "x-api-key: <uuid>" https://data.dol.gov/get/accident_abstract/limit/0 -v
This does not:
curl -H "X-API-KEY: <uuid>" https://data.dol.gov/get/accident_abstract/limit/0 -v

The servers should process headers in a case-insensitive manner.