Remove requirement for Application ID to be lowercase

[elringus]

Current setup requires the app id to be lowercase. Details can be found here: https://github.com/Elringus/UnityGoogleDrive#my-application-id-andriodios-is-mixed-cased-and-i-cant-change-it

In case anyone would like to work on this issue, feel free to ask here for any additional information.

[hippogamesunity]

I would like to avoid using workarounds. Cause my id is upper-cased)