From project root run
$ openapi-generator-cli generate \
-g kotlin-spring \
-i docs/spec/CodeCharacter-API.yml \
-c docs/spec/generator-config.yml \
--model-name-suffix=Dto \
--import-mappings=DateTime=java.time.Instant \
--type-mappings=DateTime=java.time.Instant \
-o library \
--enable-post-process-file