v1.4.0

What's Changed

• Constant current iterative method by @nitbharambe in #42
• Use internal sparse solver to replace EIGEN and MKL by @TonyXiang8787 in #77
• Simplify build process by @TonyXiang8787 in #90
• Feature/pre commit by @bramstoeller in #103
• Add isort to pre-commit by @bramstoeller in #105
• Add mypy to pre-commit (and introduce data_types.py) by @bramstoeller in #106
• Bump pypa/cibuildwheel from 2.8.1 to 2.9.0 by @dependabot in #122
• Three winding transformer by @TonyXiang8787 in #18
• update open source documentation by @nitbharambe in #124
• Remove extra_info by @bramstoeller in #126
• Release version 1.4 by @TonyXiang8787 in #87

Full Changelog: v1.3.273...v1.4.0