Update composer, bump versions and PHP7.1+

Author: barryvdh

composer.json

@@ -17,6 +17,17 @@
             "name": "Adrian Macneil",
             "email": "adrian@adrianmacneil.com"
         },
+        {
+            "name": "Barry vd. Heuvel",
+            "email": "barryvdh@gmail.com"
+        },
+        {
+            "name": "Jason Judge",
+            "email": "jason.judge@consil.co.uk"
+        },
+        {
+            "name": "Del"
+        },
         {
             "name": "Omnipay Contributors",
             "homepage": "https://github.com/thephpleague/omnipay-common/contributors"
@@ -27,18 +38,18 @@
         "classmap": ["src/Omnipay.php"]
     },
     "require": {
-        "php": "^5.6|^7",
+        "php": "^7.1",
         "php-http/client-implementation": "^1",
         "php-http/message": "^1.5",
         "php-http/discovery": "^1.2.1",
         "symfony/http-foundation": "^2.1|^3|^4",
-        "moneyphp/money": "^3.0.5"
+        "moneyphp/money": "^3.1"
     },
     "require-dev": {
         "omnipay/tests": "^3",
         "php-http/mock-client": "^1",
         "squizlabs/php_codesniffer": "^3",
-        "phpro/grumphp": "^0.12"
+        "phpro/grumphp": "^0.14"
     },
     "extra": {
         "branch-alias": {

grumphp.yml

@@ -9,7 +9,7 @@ parameters:
             always_execute: false
         phpcs:
             standard: PSR2
-            show_warnings: false
+            warning_severity: ~
             ignore_patterns:
               - tests/
             triggered_by: [php]