What's Changed
* Migrate format checking routines from cwltool by GlassOfWhiskey in https://github.com/common-workflow-language/cwl-utils/pull/141
* upgrade to mypy 0.971 by mr-c in https://github.com/common-workflow-language/cwl-utils/pull/139
* Moved kill_processes to sandbox destructor by GlassOfWhiskey in https://github.com/common-workflow-language/cwl-utils/pull/140
* rename typeshed; misc cleanups by mr-c in https://github.com/common-workflow-language/cwl-utils/pull/142
**Full Changelog**: https://github.com/common-workflow-language/cwl-utils/compare/v0.14...v0.15