Fix and improvements

Thank you for the help of @Nickolasmv

Skip: version v0.3.7 because restrictions of engine version
New feature: Allow pass associations to mutations create
Refactor: Updates and deletes mutations returns instances of affecteds records
Fix: Add * to function count
Fix: Convert to right scalar datetime type
Fix: use package-lock.json instead of yarn.lock
Fix: typos on tests files