Restore previous symfony requirements

Restore Sf support

Author: Romain Follet

.travis.yml

@@ -9,7 +9,8 @@ env:
 matrix:
     fast_finish: true
     include:
-        - php: 7.2.5
+        - php: 7.1
+        - php: 7.2
         - php: 7.3
 
 cache:

DependencyInjection/Configuration.php

@@ -26,8 +26,13 @@ class Configuration implements ConfigurationInterface
      */
     public function getConfigTreeBuilder()
     {
-        $treeBuilder = new TreeBuilder('florianv_swap');
-        $rootNode = $treeBuilder->getRootNode();
+        if (method_exists(TreeBuilder::class, 'getRootNode')) {
+            $treeBuilder = new TreeBuilder('florianv_swap');
+            $rootNode = $treeBuilder->getRootNode();
+        } else {
+            $treeBuilder = new TreeBuilder();
+            $rootNode = $treeBuilder->root('florianv_swap');
+        }
 
         $rootNode
             ->fixXmlConfig('provider')
@@ -194,10 +199,17 @@ public function getConfigTreeBuilder()
         return $treeBuilder;
     }
 
+
     private function createSimpleProviderNode($name)
     {
-        $treeBuilder = new TreeBuilder($name);
-        $node = $treeBuilder->getRootNode();
+        if (method_exists(TreeBuilder::class, 'getRootNode')) {
+            $treeBuilder = new TreeBuilder($name);
+            $node = $treeBuilder->getRootNode();
+        } else {
+            $treeBuilder = new TreeBuilder();
+            $node = $treeBuilder->root($name);
+        }
+
         $node
             ->children()
                 ->integerNode('priority')->defaultValue(0)->end()

composer.json

@@ -16,14 +16,14 @@
         "test": "vendor/bin/phpunit"
     },
     "require": {
-        "php": "^7.2.5",
-        "symfony/framework-bundle": "~5.0",
+        "php": "^5.6|^7.0",
+        "symfony/framework-bundle": "~3.0|~4.0|~5.0",
         "florianv/swap": "^4.0"
     },
     "require-dev": {
         "php-http/guzzle6-adapter": "^1.0",
         "php-http/message": "^1.7",
-        "symfony/cache": "~5.0",
+        "symfony/cache": "~3.0|~4.0|~5.0",
         "phpunit/phpunit": "~5.0",
         "nyholm/psr7": "^1.1"
     },