Update Plugins documentation (#884)

Co-authored-by: Rene Bonilla <rbonilla@assanet.com>

docs/plugins.md

@@ -11,6 +11,7 @@ Related plugins for mercurius
 - [mercurius-apollo-tracing](#mercurius-apollo-tracing)
 - [mercurius-postgraphile](#mercurius-postgraphile)
 - [mercurius-logging](#mercurius-logging)
+- [mercurius-fetch](#mercurius-fetch)
 
 ## mercurius-auth
 
@@ -145,3 +146,8 @@ A Mercurius plugin to enhance the GQL request logging adding useful insights:
 ```
 
 Check the [`mercurius-logging`](https://github.com/Eomm/mercurius-logging) documentation for usage and settings.
+
+## mercurius-fetch
+Mercurius Fetch is a plugin for [Mercurius](https://mercurius.dev) that adds fetch to a rest api directly on query or properties of query.
+
+Check the [`mercurius-fetch` documentation](https://github.com/rbonillajr/mercurius-fetch) for detailed usage.