$ oapi-codegen -config codegen.cfg.yml battleship-oapi.yaml
error parsing configuration style as old version or new version: <nil>
[1]    106688 exit 1     oapi-codegen -config codegen.cfg.yml battleship-oapi.yaml

$ oapi-codegen -config codegen.cfg.yml battleship-oapi.yaml
error parsing configuration style as old version or new version

error when parsing using old config version:
yaml: unmarshal errors:
  line 3: cannot unmarshal !!map into []string

error when parsing using new config version:
yaml: unmarshal errors:
  line 5: field server not found in type codegen.GenerateOptions
[1]    109954 exit 1     oapi-codegen -config codegen.cfg.yml battleship-oapi.yaml