Adapt are-database-scripts-in-sync CI job to minor schema version numbers

Starting with #3484 (closed), we started reusing the minor schema version numbers. The are-database-scripts-in-sync CI job was not written with minor version numbers in mind. When matching portions from the dhcpdb_create script to portions from the upgrade script, it selects a portion that is too large in the dhcpdb_create script.

In this job, it can be deduced based on the diff that it compares 21.0 -> 22.1 from dhcpdb_create to 22.0 -> 22.1 from the upgrade script, and the diff with what it expects is the lines 21.0 -> 22.0. It should have compared 22.0 -> 22.1 with 22.0 -> 22.1.

This issue happens now in v2_6, but can occur in the future in v3_0.