GraphQLTestTemplate: post() Should Be Public

[ryandanielspmc]

Is your feature request related to a problem? Please describe.

GraphQLTestTemplate seems to only allow queries to be read from files. This is very inconvenient. The class should allow inline query / mutate strings.

Describe the solution you'd like

Making post() public would seem to solve this problem.

Describe alternatives you've considered

N/A

Additional context

N/A

[oliemansm]

This has been added by @BlasiusSecundus and will be part of 8.1.0