Mask chr input to prevent deprecation warnings on PHP 8.5 (#40)

Test edge cases when unpacking map keys

Improve PackingFailedException message

Tweak README.md

Tweak README.md

Switch to travis-ci.com

See https://blog.travis-ci.com/2018-05-02-open-source-projects-on-travis-ci-com-with-github-apps

Optimize checking array emptiness

Prioritize transformers over raw extensions while packing

Tweak examples

Update license year