* fix(ktor-client): do not add jsonBlock if using kotlinx-serialization
* update existing templates
* add new kotlin-jvm-ktor-kotlinx_serialization
* add new kotlin-jvm-ktor-kotlinx_serialization to samples-kotlin-client.yaml pipeline
actually, kotlin-jvm-ktor-gson was duplicated, so I'm replacing the second one by kotlin-jvm-ktor-kotlinx_serialization
* extra FILES entry in the template
* enumUnknownDefaultCase=false for now since it's currently broken for ktor + kotlinx_serialization
* use openapi 3 petstore
