Update require version

Author: Mingeun Kim

composer.json

@@ -8,12 +8,12 @@
     ],
     "type": "library",
     "require": {
-        "php": ">=5.5.9",
-        "illuminate/support": ">=5.1",
-        "illuminate/console": ">=5.1"
+        "php": "^7.1",
+        "illuminate/support": "~5.6.34|~5.7.0|~5.8.0|^6.0|^7.0",
+        "illuminate/console": "~5.6.34|~5.7.0|~5.8.0|^6.0|^7.0"
     },
     "require-dev": {
-        "phpunit/phpunit": "~4.0"
+        "phpunit/phpunit": "^7.0|^8.0|^9.0"
     },
     "license": "MIT",
     "authors": [