A function to assign or re-assign the API key. Register for an API key on the Guardian Open Platform site.
By default, guardianapi will look for the GU_API_KEY
environmental variable when the package is loaded. If found the key is stored
in the session option gu.API.key. This function can be used to set the key
for a single session. To avoid having to use this function, use the .Renviron
file to store you key as GU_API_KEY.
gu_api_key(check_env = FALSE)If TRUE, will check the environment variable GU_API_KEY
first before asking for user input. If found, assigns the API key to the
gu.API.key variable.