minor symfony#17712 [TwigBridge] fix default argument value (xabbuh)

This PR was merged into the 3.1-dev branch.

Discussion
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[TwigBridge] fix default argument value

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | symfony#17705
| License       | MIT
| Doc PR        |

When deprecating boolean argument values, the default value must not be
`false`.

Commits
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beea61e [TwigBridge] fix default argument value

Author: xabbuh

src/Symfony/Bridge/Twig/Extension/YamlExtension.php

@@ -31,7 +31,7 @@ public function getFilters()
         );
     }
 
-    public function encode($input, $inline = 0, $dumpObjects = false)
+    public function encode($input, $inline = 0, $dumpObjects = 0)
     {
         static $dumper;