v0.12.0

What's Changed

• #39: implement explicit custody by @pydsigner in #40
• Handle error case when multiple image types are output from one Pillow step by @pydsigner in #41
• #27, #28: Support fetching and unpacking external resources by @pydsigner in #42, #43
• #31: Add an extended Markdown rendering Step by @pydsigner in #44

Full Changelog: v0.11.0...v0.12.0