Remove MongoDB 6.0 docker build.

See #4956

Author: mp911de

ci/pipeline.properties

@@ -7,7 +7,6 @@ docker.java.main.image=library/eclipse-temurin:${java.main.tag}
 docker.java.next.image=library/eclipse-temurin:${java.next.tag}
 
 # Supported versions of MongoDB
-docker.mongodb.6.0.version=6.0.23
 docker.mongodb.7.0.version=7.0.20
 docker.mongodb.8.0.version=8.0.9