Update composer.json

composer seems to have failed build, reverting to previous mockery version which seemed to pass

Author: malteriesch

composer.json

@@ -14,7 +14,7 @@
 
     },
     "require-dev": {
-	"mockery/mockery": "0.9.*"
+	"mockery/mockery": "0.8.*"
     },
     "autoload": {
         "psr-0": { "TestDbAcle": "lib/" }