SonarQube 10.6 emits a warning about using getStringArray to read file suffixes

[testworksau]

We are seeing this message in our scans since upgrading to SonarQube 10.6:

WARN: Property 'sonar.ps.file.suffixes' is not declared as multi-values/property set 
but was read using 'getStringArray' method. The SonarQube plugin declaring this 
property should be updated.

It looks like this is the line that triggers the warning:

sonar-ps-plugin/sonar-ps-plugin/src/main/java/org/sonar/plugins/powershell/PowershellLanguage.java

Line 22 in 446e715

final String[] suffixes = this.settings.getStringArray(Constants.FILE_SUFFIXES);

We are not sure if 10.6 introduced the problem; it could just be a coincidence that we noticed it after our upgrade.

This PR should fix the problem:
#33

[testworksau]

@gretard is there anything further that we can do to help get a release of this please? 🙏🏼