Issue type:

[ ] question
[X] bug report
[ ] feature request
[ ] documentation issue

Database system/driver:

[ ] cordova
[ ] mongodb
[ ] mssql
[ ] mysql / mariadb
[ ] oracle
[X] postgres
[ ] cockroachdb
[ ] sqlite
[ ] sqljs
[ ] react-native
[ ] expo

TypeORM version:

[ ] latest
[X] @next
[ ] 0.x.x (or put your version here)

Steps to reproduce or a small repository showing the problem:

/src/driver/postgres/PostgresDriver.ts Line 820 function 'findChangedColumns'
Changing checking doesn't count in alter one column 'array' attribute.