Bump required PHP version to 7.1

sebastiandedeyne · sebastiandedeyne · commit 5c0e414ce2de · 2019-01-29T12:45:47.000+01:00
diff --git a/composer.json b/composer.json
@@ -20,7 +20,7 @@
         }
     ],
     "require": {
-        "php": "^7.0",
+        "php": "^7.1",
         "phpunit/phpunit": "^6.0.5|^7.0"
     },
     "autoload": {
