Merge pull request #812 from murtukov/0.11

[0.11] Combine all UPGRADE files

Author: murtukov

UPGRADE-0.10.md

@@ -274,3 +274,22 @@ UPGRADE FROM 0.10 to 0.11
   **Before 0.11**: `'@=resolver("App\\GraphQL\\Resolver\\Greetings", [args['name']])'`
 
   **Since 0.11**: `'@=resolver("app.resolver.greetings", [args['name']])'`
+
+
+UPGRADE FROM 0.9 to 0.10
+=======================
+
+# Table of Contents
+
+- [Symfony](#symfony)
+
+### Symfony
+
+* Minimal supported Symfony version is now `^3.1 || ^4.0`
+
+  We've dropped support for Symfony 2.8 and 3.0
+
+Upgrading your Symfony version:
+- [Upgrading to Symfony 3.0](https://github.com/symfony/symfony/blob/master/UPGRADE-3.0.md)
+- [Upgrading to Symfony 3.1](https://github.com/symfony/symfony/blob/master/UPGRADE-3.1.md)
+