Update CHANGELOG.md

Merge pull request laravel#73 from Vendin/up-use-composer-vendor-dir

Use COMPOSER_VENDOR_DIR

update versions

formatting

remove block

Merge pull request laravel#44 from laravel/psysh-update

Allow psysh 0.9

Make sure config merging takes place

formatting

allow symfony 4

Merge pull request laravel#20 from henriquebremenkanp/patch-1

Replace fire() with handle() for 5.5 compatibility