docs: update readme

Author: jlalmes

README.md

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+#### `trpc-openapi` is maintained by ProsePilot - simple, fast and free online [writing tools](https://www.prosepilot.com/tools).
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 ## **[OpenAPI](https://swagger.io/specification/) support for [tRPC](https://trpc.io/)** 🧩
 
 - Easy REST endpoints for your tRPC procedures.