Create 2.7 upgrade headline for deprecation changes

UPGRADE.md

@@ -1,3 +1,10 @@
+# Upgrade to 2.7
+
+## Deprecated: `Doctrine\ORM\EntityManagerInterface#copy()`
+
+Method `Doctrine\ORM\EntityManagerInterface#copy()` never got its implementation and is deprecated.
+It will be removed in 3.0.
+
 # Upgrade to 2.6
 
 ## Added `Doctrine\ORM\EntityRepository::count()` method
@@ -37,11 +44,6 @@ As a consequence, automatic cache setup in Doctrine\ORM\Tools\Setup::create*Conf
 - Memcached extension (ext-memcached) will be used instead of obsolete Memcache (ext-memcache).
 - XCache support was dropped as it doesn't work with PHP 7.
 
-## Deprecated: `Doctrine\ORM\EntityManagerInterface#copy()`
-
-Method `Doctrine\ORM\EntityManagerInterface#copy()` never got its implementation and is deprecated.
-It will be removed in 3.0.
-
 # Upgrade to 2.5
 
 ## Minor BC BREAK: removed `Doctrine\ORM\Query\SqlWalker#walkCaseExpression()`