Merge branch '4.2' into 4.3

* 4.2:
  fix Debug component dependencies
  [travis] not all components have a master branch

Author: xabbuh

composer.json

@@ -20,6 +20,7 @@
         "ext-xml": "*",
         "symfony/cache": "~4.3",
         "symfony/config": "~4.2",
+        "symfony/debug": "~4.0",
         "symfony/dependency-injection": "^4.3",
         "symfony/http-foundation": "^4.3",
         "symfony/http-kernel": "^4.3",