Configuration format has changed since version 4.0 of the license check plugin. From the plugin's website:

NOTE: Between versions 4.0 and 3.0 the configuration syntax has been
changed. The plugin now has the concept of License Sets, which allow you
to work with one or more license configurations in a single execution of
the plugin. In simple terms, a wraps the previous
configuration options for a license.

Updating the format gets rid of the following warnings in our builds:

[WARNING] Parameter 'legacyConfigExcludes' (user property 'license.excludes') is deprecated: use LicenseSet.excludes
[WARNING] Parameter 'legacyConfigHeader' (user property 'license.header') is deprecated: use LicenseSet.header
[WARNING] Parameter 'legacyConfigIncludes' (user property 'license.includes') is deprecated: use LicenseSet.includes

Same as https://github.com/SonarSource/parent/pull/177