prefix attribute for directory node missing from phpunit.xml XSD

[adampraszywka]

Q	A
PHPUnit version	7.2.7
PHP version	7.2.6
Installation Method	Composer

After updating PHPUnit to version 7.2 every test run produces warning about invalid configuration file.

Warning - The configuration file did not pass validation!
  The following problems have been detected:

  Line 18:
  - Element 'directory', attribute 'prefix': The attribute 'prefix' is not allowed.

Testsuites configuration:

   <testsuites>
        <testsuite name="Unit">
            <directory prefix="U">tests</directory>
        </testsuite>
        <testsuite name="Integration">
            <directory prefix="I">tests</directory>
        </testsuite>
        <testsuite name="DB">
            <directory prefix="DB">tests</directory>
        </testsuite>
        <testsuite name="Functional">
            <directory prefix="F">tests</directory>
        </testsuite>
        <testsuite name="SQLTest">
            <directory prefix="SQL">tests</directory>
        </testsuite>
    </testsuites>

I use prefix attribute to run TestCase files with specified prefix.

I guess it is connected with configuration validation added in version 7.2 #3048
Prefix attribute doesn't exist in XSD file.
Does this mean that we I use deprecated or forgotten function ?
Is there any way to achieve the same behavior using different configuration options ?