spruce-release Release v1.21.0

Improvements

• spruce diff is now powered by github.com/homeport/dyff/pkg/v1/dyff.
  There are new and fancy diffing capabilities, like changes in order of a list.
  Output also is improved a bit. Fixes #285. You can see it in action at
  https://user-images.githubusercontent.com/1979133/59055557-6277c880-8896-11e9-9ddd-8a8606a31452.png

Acknowledgements

Many thanks @HeavyWombat for the PR!