Remove PHP 7.0 support (#69)

Author: TavoNiievez

composer.json

@@ -12,7 +12,7 @@
     ],
     "minimum-stability": "RC",
     "require": {
-        "php": ">=7.0.8 <9.0",
+        "php": ">=7.1.3 <9.0",
         "codeception/lib-innerbrowser": "^1.3",
         "codeception/codeception": "^4.0",
         "ext-json": "*"