message: update changelog to add release
diff: # Unreleased Features
  Please add a note of your changes below this heading if you make a Pull Request.
  +# Releases
  +## [0.4.9] - 2019-04-23
  ### Added
  * A release target for ODrive v3.6
  * Communication watchdog feature.
  @@ -16,7 +18,6 @@ Please add a note of your changes below this heading if you make a Pull Request.
  ### Fixed
  * Encoder index interrupts now disabled when not searching
  -# Releases
  ## [0.4.8] - 2019-02-25
  ### Added
  * `dump_errors()` utility function in odrivetool to dump, decode and optionally clear errors.
  