message: improve README language
diff: @@ -86,13 +86,12 @@ splunkOnCall:
  readOnly: true
  proxy:
  - # ...
  '/splunk-on-call':
  target: https://api.victorops.com/api-public
  headers:
  X-VO-Api-Id: ${SPLUNK_ON_CALL_API_ID}
  X-VO-Api-Key: ${SPLUNK_ON_CALL_API_KEY}
  - # prohibit non-GET requests from the /splunk-on-call proxy
  + # prohibit the `/splunk-on-call` proxy endpoint from servicing non-GET requests
  allowedMethods: ['GET']
  ```
  