Correct minimum MariaDB version for CHECK_CONSTRAINTS

[elebow]

Summary

According to the MariaDB documentation, CHECK_CONSTRAINTS is not supported until 10.2.22. https://mariadb.com/kb/en/information-schema-check_constraints-table/

[fatkodima]

Check constraints are supported from 10.2.1, we only shouldn't use the check_constraints table to get them.
Do you want to update this PR with the suggested change?

[yahonda]

I prefer this change to require newer maintenance versions of MariaDB rather than adding fixes for old maintenance versions of MariaDB like 10.2.1.

Would you add a changelog for this change?
CHECK_CONSTRAINTS has been added to MariaDB 10.3.10, so let's return false for MariaDB 10.3.9 or older versions of MariaDB 10.3 series.

[elebow]

Updated version check for 10.3.x and added changelog entry.

[yahonda]

How about "Adjust the minimum MariaDB version for check constraints support." ? CHECK_CONSTRAINTS is something internal one, not for Rails application developers.

[elebow]

Updated.