Upgrade SonarQube API to latest LTS 5.6

[benzonico]

No description provided.

[dbmeneses]

The SonarQube API that was deprecated before version 5.6 will dropped soon.
It can be tested with SonarQube artifact 7.0.0.34895 (or newer one from the branch 'feature/dm/sq56').

More information: https://jira.sonarsource.com/browse/SONAR-10138

[alixwar]

6.7 is the new LTS version. Seems to work still somewhat?

[dbmeneses]

It probably works even with the latest version 7.0 because the old API hasn't been removed yet, but it might be removed soon and the plugin will then be broken.