message: add link to best practices
diff: -[Delete any non-applicable sections, but we may ask for more information.]
  +[Delete any non-applicable sections, but we may ask for more information. Please reference the [SmartDeviceLink GitHub Best Practices](https://d83tozu1c8tt6.cloudfront.net/media/resources/SDL_GitHub_BestPractices.pdf) for further instructions on how to enter an issue.]
  ### Bug Report
  [Summary]
  