Changes since 2.1.0: https://github.com/wikimedia/object-factory/compare/v2.1.0...v3.0.0
Notable changes:
Support for optional services
Removed deprecated `constructClassInstance` method
Allow null values for 'services' spec field
Drop PHP 7.0/7.1 and HHVM support
Checklist:
[x] Update HISTORY.md {icon check-square color=green} [patch](https://gerrit.wikimedia.org/r/plugins/gitiles/mediawiki/libs/ObjectFactory/+/0d2c4efc08e80485e5f7b1665fe473375e242017)
[x] Tag new version {icon check-square color=green} [Tagged by @Jdforrester-WMF](https://gerrit.wikimedia.org/r/plugins/gitiles/mediawiki/libs/ObjectFactory/+/refs/tags/v3.0.0)
[] Update Parsoid to accept either old or new version of ObjectFactory
[] Update vendor with new version of Parsoid
[] Update vendor with new version of ObjectFactory
[] Update core with new version of ObjectFactory