message: Update readme.md
  fixed `output-folder` to what suggests is desired
diff: @@ -25,6 +25,6 @@ These settings apply only when `--csharp` is specified on the command line.
  ``` yaml $(csharp)
  csharp:
  namespace: Microsoft.CognitiveServices.EntitySearch
  - output-folder: out/csharp
  + output-folder: $(csharp-sdks-folder)/CognitiveServices/dataPlane/Search/Search/Generated/EntitySearch
  ```
  