Sonarcloud: Ignore 3rdparty folder

Signed-off-by: Felix Weilbach <felix.weilbach@nextcloud.com>

sonar-project.properties

@@ -1,6 +1,7 @@
 sonar.projectKey=nextcloud_desktop
 sonar.organization=nextcloud
 sonar.sources=src
+sonar.exclusions=3rdparty/**
 sonar.language=c++
 sonar.cfamily.cache.enabled=false
 sonar.cfamily.threads=2