minor #29880 [TwigBridge] bump required Twig version (xabbuh)

This PR was merged into the 3.4 branch.

Discussion
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[TwigBridge] bump required Twig version

| Q             | A
| ------------- | ---
| Branch?       | 4.1
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | twigphp/Twig#2810
| License       | MIT
| Doc PR        |

Commits
-------

37e8ccb bump required Twig version

src/Symfony/Bridge/Twig/composer.json

@@ -17,7 +17,7 @@
     ],
     "require": {
         "php": "^5.5.9|>=7.0.8",
-        "twig/twig": "^1.36.1|^2.6.1"
+        "twig/twig": "^1.37.1|^2.6.2"
     },
     "require-dev": {
         "symfony/asset": "~2.8|~3.0|~4.0",