upgrade okhttp-gson and google-api-client to junit5
PR for okhttp-gson and google-api-client of #18470
This error is https://petstore.swagger.io/ blocking circle-ci again.
i've restarted the job. let's see how that goes
(circleci uses a local petstore server with updated host table in the vm)
https://github.com/OpenAPITools/openapi-generator/actions/runs/9009746571/job/24758770345?pr=18618
please update samples too.
please have a look at https://github.com/OpenAPITools/openapi-generator/actions/runs/9019579968/job/24782776638?pr=18618 when you've time
merged via https://github.com/OpenAPITools/openapi-generator/pull/18668 instead