Read headers from config object

[adam-cowley]

Gives the ability to provide a map of HTTP headers on the config property for HTTP requests.

WITH { `X-API-KEY`: 'abc123' } as headers,
WITH "https://myapi.com/api/v1/" AS url
CALL apoc.load.xml(url, '', { headers: headers }) YIELD value
UNWIND keys(value) AS key
RETURN key, apoc.meta.type(value[key]);

[jexp]

Thanks a lot Adam!