Statman

What's Changed
* support external function based metric by jasonray in https://github.com/jasonray/statman.py/pull/79
* metric base class by jasonray in https://github.com/jasonray/statman.py/pull/67
* Bump pylint from 3.0.2 to 3.0.3 by dependabot in https://github.com/jasonray/statman.py/pull/77


**Full Changelog**: https://github.com/jasonray/statman.py/compare/v1.3.1...v1.4.0

What's Changed
* Update README.md by jasonray in https://github.com/jasonray/statman.py/pull/66
* Feature/51 metric base class by jasonray in https://github.com/jasonray/statman.py/pull/67

**Full Changelog**: https://github.com/jasonray/statman.py/compare/v1.3.1...v1.3.2

What's Changed
* include python 3.8 on CI build by jasonray in https://github.com/jasonray/statman.py/pull/60
* Documentation updates by jasonray in https://github.com/jasonray/statman.py/pull/56
* defect fix: handle mutating registry during reporting by jasonray in https://github.com/jasonray/statman.py/pull/61
* Feature/50 rate calculation metric by jasonray in https://github.com/jasonray/statman.py/pull/62

**Full Changelog**: https://github.com/jasonray/statman.py/compare/v0.2.0...v1.3.0

Introduce calculation metric

Support report delegate to log message