Update dependencies to symfony 4.x

Author: shaundrong

composer.json

@@ -38,17 +38,17 @@
     }
   },
   "require": {
-    "php": ">=5.4",
-    "alchemy/zippy": "^0.3",
-    "doctrine/collections": "1.4.0",
+    "php": ">=7.1",
+    "alchemy/zippy": "^1.0",
+    "doctrine/collections": "^1.6",
     "kevinlebrun/colors.php": "^1.0",
-    "michelf/php-markdown": "^1.6",
-    "seld/jsonlint": "^1.0",
+    "michelf/php-markdown": "^1.9",
+    "seld/jsonlint": "^1.8",
     "shudrum/array-finder": "^1.0",
-    "symfony/event-dispatcher": "^3.0",
-    "symfony/filesystem": "^3.0",
-    "symfony/finder": "^3.0",
-    "symfony/process": "^3.1",
-    "symfony/yaml": "^3.0"
+    "symfony/event-dispatcher": "^4.4",
+    "symfony/filesystem": "^4.4",
+    "symfony/finder": "^4.4",
+    "symfony/process": "^4.4",
+    "symfony/yaml": "^4.4"
   }
 }