[3.0][Console] Added isVerbosity* to OutputInterface

Now, only `Output` have theses methods. But in the `Command` class, `execute` receive an instance of `OutputInterface`. So, to avoid coding an implementation, theses method should be added to the interface.

Author: lyrixx

UPGRADE-3.0.md

@@ -18,6 +18,11 @@ UPGRADE FROM 2.x to 3.0
    `DebugClassLoader`. The difference is that the constructor now takes a
    loader to wrap.
 
+### Console
+
+ * The methods `isQuiet`, `isVerbose`, `isVeryVerbose` and `isDebug` were added
+   to `Symfony\Component\Console\Output\OutputInteface`.
+
 ### EventDispatcher
 
  * The interface `Symfony\Component\EventDispatcher\Debug\TraceableEventDispatcherInterface`