Fix(react-query): ensure mutationKey is always array

[jonathanstanley]

Describe the bug
React Query is requiring queryKeys and mutationKeys to always be an array. see:
TanStack/query#2919

To Reproduce
Use with React Query v4 (currently alpha) will throw type errors.

Expected behavior
Use an array for the keys instead of a string. i.e. ['mystring'] instead of 'mystring'

Environment:
any

Additional context
v4 is currently in pre-release and will become more pressing once released. This is a backwards-compatible upgrade... arrays have always been an acceptable key.

[charlypoly]

@jonathanstanley Thank you for your contribution, it has been released in @graphql-codegen/typescript-react-query@3.4.0 📦