Add 'ANY' operator for strings

[avi-city]

Hello,
First of all thanks for maintaining this library. At Seemplicity we are using your library to enable our customers filtering their data using the Graphql API we are providing.
We saw that in some use cases, there is an improvement in performance for using "Any" instead of "In" (as you can see in the following Stackoverflow answer). I think it might be a nice addition to enable both options for String fields.
Please let me know what you think.

P.s.
The version bump is because we are using it internally and I wanted it to be more clear which version is being used. Let me know if you need me to remove it.

Thanks!
Avi

[palisadoes]

@avi-city there has not been much activity on this repo recently. U;ve tried to contact art1415926535 many times without success to assist with updates. Would you be interested in a sponsored engagement to integrate this repo into graphene-sqlalchemy as a standard feature set?