Update task news to support 3.0.0 (#3342)

* Introduce Version, use it to check current version in custom reports
* Support multiple versions in 'task news'

src/CMakeLists.txt

@@ -18,6 +18,7 @@ add_library (task STATIC CLI2.cpp CLI2.h
                   TDB2.cpp TDB2.h
                   Task.cpp Task.h
                   Variant.cpp Variant.h
+                  Version.cpp Version.h
                   ViewTask.cpp ViewTask.h
                   dependency.cpp
                   feedback.cpp