[Go] Set Default Values for Required Variables when a default is defined

[vvb]

Fixes #19107

• useDefaultValuesForRequiredVars flag is added to enable this behavior. It is disabled by default.
• Samples that have a required value would have some diff from before if the flag is set to true

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

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  Commit all changed files.
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[Ghufz]

Looks good to me

[wing328]

for the failing test, please update the assertion accordingly as the Category name will have the default value after this change (with the option enabled)

[vvb]

for the failing test, please update the assertion accordingly as the Category name will have the default value after this change (with the option enabled)

I have removed the setting of the value and Getter is a pure getter as it should have been. So, this is not required anymore.

[wing328]

please run https://github.com/OpenAPITools/openapi-generator/blob/master/bin/utils/ensure-up-to-date to update the doc as well

[vvb]

please run https://github.com/OpenAPITools/openapi-generator/blob/master/bin/utils/ensure-up-to-date to update the doc as well

@wing328 I had missed out running the exporting of docs post resolving the comments. It is done now. And all the tests are passing.

[wing328]

looks good. let's give it a try