feature #46 Use symfony/lts for 3.3 branch too (ostrolucky)

This PR was merged into the 3.3 branch.

Discussion
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Use symfony/lts for 3.3 branch too

`composer create-project symfony/skeleton test "3.3.*"` as specified in example in http://symfony.com/doc/current/setup.html currently downloads `4.*` packages

Commits
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411e5d6 Use symfony/lts for 3.3 branch too

Author: fabpot

composer.json

@@ -9,6 +9,7 @@
         "symfony/console": "^3.3",
         "symfony/flex": "^1.0",
         "symfony/framework-bundle": "^3.3",
+        "symfony/lts": "^3",
         "symfony/yaml": "^3.3"
     },
     "require-dev": {