Ignore complaints about dead code

We've declared types in phpdoc, but they are not enforced by type
declarations, so we are enforcing them with checks. Psalm complains it
is dead code because it assumes the types can be trusted.

psalm.xml

@@ -15,4 +15,12 @@
             <directory name="vendor" />
         </ignoreFiles>
     </projectFiles>
+    <issueHandlers>
+        <NoValue>
+            <errorLevel type="suppress">
+                <file name="lib/Doctrine/Common/Annotations/Annotation/Enum.php" />
+                <file name="lib/Doctrine/Common/Annotations/Annotation/Target.php" />
+            </errorLevel>
+        </NoValue>
+    </issueHandlers>
 </psalm>