Merge pull request #18 from denis-sokolov/patch-1

Fixup installation success check in the docs

Author: brendo

README.md

@@ -330,7 +330,7 @@ plugins:
 You can confirm the plugin is correctly installed by running:
 
 ```bash
-serverless | grep "ServerlessOpenAPIDocumentation"
+serverless | grep -i "ServerlessOpenAPIDocumentation"
 ```
 
 It should return `ServerlessOpenAPIDocumentation` as one of the plugins on the list.