Use proper exit code for composer lint

Signed-off-by: Morris Jobke <[email protected]>

composer.json

@@ -7,6 +7,6 @@
     "classmap-authoritative": true
   },
   "scripts": {
-    "lint": "find . -name \\*.php -not -path './vendor/*' -exec php -l \"{}\" \\;"
+    "lint": "find . -name \\*.php -not -path './vendor/*' -print0 | xargs -0 -n1 php -l"
   }
 }