chore: prepare release, bump version

sonar-project.properties

@@ -2,7 +2,7 @@
 sonar.projectKey=owncloud_ocis
 sonar.organization=owncloud-1
 sonar.projectName=ocis
-sonar.projectVersion=5.1.0-prealpha
+sonar.projectVersion=6.0.0
 sonar.host.url=https://sonarcloud.io
 
 # =====================================================
@@ -50,4 +50,4 @@ sonar.issue.ignore.multicriteria.g2.resourceKey=**/*_test.go
 
 # Timeout for web requests
 #sonar.ws.timeout=60 is the default, but we need to increase it to deal with timeouts when loading defaults
-sonar.ws.timeout=120
+sonar.ws.timeout=120