Fix grammer (#607)

Author: esambo

Diff for: README.md

@@ -282,7 +282,7 @@ mix openapi.spec.yaml --spec MyAppWeb.ApiSpec
 Invoking this task starts the application by default. This can be
 disabled with the `--start-app=false` option.
 
-Please make to replace any calls to [OpenApiSpex.Server.from_endpoint](https://hexdocs.pm/open_api_spex/OpenApiSpex.Server.html#from_endpoint/1) with a `%OpenApiSpex.Server{}` struct like below:
+Please replace any calls to [OpenApiSpex.Server.from_endpoint](https://hexdocs.pm/open_api_spex/OpenApiSpex.Server.html#from_endpoint/1) with a `%OpenApiSpex.Server{}` struct like below:
 
 ```elixir
   %OpenApi{