Documentation: Not clear how to provide the API key

[gajus]

https://github.com/geocoder-php/Geocoder/blob/master/README.md Geocoder\Provider\GoogleMaps example fails to show that the last parameter is the API key. Had to take a look at the source code to find it, https://github.com/geocoder-php/Geocoder/blob/master/src/Geocoder/Provider/GoogleMaps.php#L56.

[toin0u]

Thank you for the report @gajus :)