message: Fix example in README.
diff: @@ -29,7 +29,7 @@ While working locally, you may wish to hard-code your API key in your
  ```yaml
  # app-config.local.yaml
  proxy:
  - 'newrelic/apm/api':
  + '/newrelic/apm/api':
  headers:
  X-Api-Key: NRRA-YourActualApiKey
  ```
  