chore: add oapi-codegen (#5036)

* chore: add oapi-codegen

Useful utility to generate go models based on openapi spec

* fix: move pkg up as per alphabetical order

* fix: category

* punctuation

README.md

@@ -1176,6 +1176,7 @@ _Tools that generate Go code._
 - [GoWrap](https://github.com/hexdigest/gowrap) - Generate decorators for Go interfaces using simple templates.
 - [interfaces](https://github.com/rjeczalik/interfaces) - Command line tool for generating interface definitions.
 - [jennifer](https://github.com/dave/jennifer) - Generate arbitrary Go code without templates.
+- [oapi-codegen](https://github.com/deepmap/oapi-codegen) - This package contains a set of utilities for generating Go boilerplate code for services based on OpenAPI 3.0 API definitions.
 - [typeregistry](https://github.com/xiaoxin01/typeregistry) - A library to create type dynamically.
 
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