Update OAS Validator/Generator

[nils-work]

Description
The current OAS generate script (swagger-gen\oas_generate.sh) doesn't clearly specify the OpenAPI Generator jar file version used for validating and generating the OAS output in the Standards build process.

The version details should be updated and aligned.

Validate OAS version

- VALID_OAS=$(java -jar $OAS_CODEGEN/openapi-generator-cli.jar validate -i $INPUT_SWAGGER)
+ VALID_OAS=$(java -jar $OAS_CODEGEN/openapi-generator-cli-6.6.0.jar validate -i $INPUT_SWAGGER)

Key change above is:

- openapi-generator-cli.jar
+ openapi-generator-cli-6.6.0.jar

Generate OAS version

- java -jar $OAS_CODEGEN/openapi-generator-cli-5.2.1.jar generate -i $INPUT_SWAGGER -g $OUTPUT_FORMAT -o $SWAGGER_CODEGEN_OUTPUT > $SWAGGER_CODEGEN_OUTPUT/log.txt 2>&1
+ java -jar $OAS_CODEGEN/openapi-generator-cli-6.6.0.jar generate -i $INPUT_SWAGGER -g $OUTPUT_FORMAT -o $SWAGGER_CODEGEN_OUTPUT > $SWAGGER_CODEGEN_OUTPUT/log.txt 2>&1

Key change above is:

- openapi-generator-cli-5.2.1.jar
+ openapi-generator-cli-6.6.0.jar

The newer version provides improved schema validation detail and on generation improves output formatting with clearer nested schema references.

[nils-work]

Validation only was updated to the newer version in Standards 1.32.0.

#445 - Update the OAS Generator jar version will consider the change to the generate version.