Merge branch '5.0'

* 5.0:
  Tweak the code to avoid fabbot false positives
  Remove UPGRADE files for 4.x

Author: fabpot

Data/Bundle/Reader/JsonBundleReader.php

@@ -46,7 +46,7 @@ public function read(string $path, string $locale)
         $data = json_decode(file_get_contents($fileName), true);
 
         if (null === $data) {
-            throw new RuntimeException(sprintf('The resource bundle "%s" contains invalid JSON: %s.', $fileName, json_last_error_msg()));
+            throw new RuntimeException(sprintf('The resource bundle "%s" contains invalid JSON: '.json_last_error_msg(), $fileName));
         }
 
         return $data;