minor #13777 [PhpUnitBridge] Allow PHP 5.3.3 to use with Symfony 2.3 (nicolas-grekas)

This PR was merged into the 2.7 branch.

Discussion
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[PhpUnitBridge] Allow PHP 5.3.3 to use with Symfony 2.3

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

Commits
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25aa12d [PhpUnitBridge] Allow PHP 5.3.3 to use with Symfony 2.3

src/Symfony/Bridge/PhpUnit/composer.json

@@ -16,7 +16,7 @@
         }
     ],
     "require": {
-        "php": ">=5.3.9"
+        "php": ">=5.3.3"
     },
     "suggest": {
         "symfony/debug": "For tracking deprecated interfaces usages at runtime with DebugClassLoader"