Log Message:
Update ruby-mini-magick to 4.4.0.

4.4.0

* Using MiniMagick::Image#format now works when the image instance is a
  layer/frame/page.
* Calling MiniMagick::Tool#clone as a way of adding the -clone CLI option now
  works properly (before it would call Object#clone).
* Badly encoded lines in identify -verbose don't cause an error anymore in
  MiniMagick::Image#details.
* MiniMagick::Image#details doesn't hang anymore when clipping paths are
  present
* Added MiniMagick::Image#tempfile for accessing the underlying temporary
  file.