Support var-dumper 4.x (#3578)

Author: Chi-teck

composer.json

@@ -42,7 +42,7 @@
     "symfony/event-dispatcher": "~2.7|^3",
     "symfony/finder": "~2.7|^3",
     "symfony/process": "~2.7|^3",
-    "symfony/var-dumper": "~2.7|^3",
+    "symfony/var-dumper": "~2.7|^3|^4",
     "symfony/yaml": "~2.3|^3",
     "webflo/drupal-finder": "^1.1",
     "webmozart/path-util": "^2.1.0"

isolation/composer.json

@@ -10,7 +10,7 @@
     "ext-dom": "*",
     "psr/log": "~1.0",
     "consolidation/config": "^1.0.9",
-    "symfony/var-dumper": "~2.7|^3",
+    "symfony/var-dumper": "~2.7|^3|^4",
     "symfony/finder": "~2.7|^3",
     "webflo/drupal-finder": "^0",
     "webmozart/path-util": "^2.1.0",