Update plugin properties to declare them as multi-values property

[Evangelink]

When running the scanner for msbuild against a recent version of SonarQube the analysis will display the following kind of warnings: WARNING: WARN: Property 'sonar.cs.opencover.reportsPaths' is not declared as multi-values/property set but was read using 'getStringArray' method. The SonarQube plugin declaring this property should be updated.. These warnings can be a concern for end-users while they are only targeting plugin developers and so should be fixed ASAP.

[markdemich]

Are these warning benign though?

[Evangelink]

Hi @markdemich,

They are! They are only related to an internal change of API on the plugins and are meant to help us (developers) to see that we haven't updated the usage.