docs: update readme and changelog and version number (#718)

* Update readme and changelog and version number

* style: pre-commit.ci fixes

* fix missing references

* style: pre-commit.ci fixes

* merge in changes from non existent 2.1.3 patch release

* Update CHANGELOG.md

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Henry Schreiner <HenrySchreinerIII@gmail.com>
Co-authored-by: Henry Schreiner <henry.fredrick.schreiner@cern.ch>