Update CHANGELOG.md in preparation for 0.45.0 release
Update CHANGELOG.md in preparation for 0.45.0 release

dipinhora/ponyc,jemc/ponyc,sgebbie/ponyc,sgebbie/ponyc,dipinhora/ponyc,ponylang/ponyc,sgebbie/ponyc,ponylang/ponyc,sgebbie/ponyc,ponylang/ponyc,jemc/ponyc,dipinhora/ponyc,sgebbie/ponyc,jemc/ponyc