Issue 69 fix allow arg and args properties

[spacether]

Issue 69 fix allow arg and args properties
Thank you @MustansirS for your original fix in OpenAPITools/openapi-generator#13955
This is a copy of that fix in the new repo location

PR checklist

• Read the contribution guidelines.
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  ./mvnw clean package 
  ./bin/generate-samples.sh
  ./bin/utils/export_docs_generators.sh
  

  Commit all changed files.
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