message: Document log env varible change
diff: @@ -4,6 +4,10 @@ Any changes, including backwards incompatible changes will be listed here
  ## 10.1.0 (17/02/2019)
  +- Log destination can now be assigned via env variable `LOG_DESTINATION`
  + - `"/absolute/path/to/file"` logs to file
  + - `"stdout"` logs to stdout
  + - `"perf"` logs to stdout in [extreme mode](https://github.com/pinojs/pino/blob/master/docs/extreme.md)
  - Added ability to export prometheus metrics by basic auth protected `/metrics` endpoint. To enable include `PROMETHEUS_USERNAME` and `PROMETHEUS_PASSWORD` as environment variables. Those environment variables are required to authenticate using [HTTP basic authentication](https://developer.mozilla.org/en-US/docs/Web/HTTP/Authentication)
  - Dropped bunyan as dependency. Replaced with pino, a faster and actively maintained logging library
  - Updated dependencies
  