Require PHP 7.1 and update dependencies

composer.json

@@ -23,7 +23,7 @@
         }
     ],
     "require": {
-        "php": "^5.5|^7.0",
+        "php": "^7.1",
         "ext-pdo": "*",
         "ext-curl": "*",
         "ext-json": "*",
@@ -32,7 +32,7 @@
         "guzzlehttp/guzzle": "^6.3"
     },
     "require-dev": {
-        "phpunit/phpunit": "^4.8|^5.7|^6.5|^7.5|^8.1",
+        "phpunit/phpunit": "^7.5",
         "squizlabs/php_codesniffer": "^3.4"
     },
     "autoload": {
@@ -58,5 +58,11 @@
         "test-cov-upload": [
             "wget https://scrutinizer-ci.com/ocular.phar && php ocular.phar code-coverage:upload --format=php-clover build/logs/clover.xml"
         ]
+    },
+    "config": {
+        "platform": {
+            "php": "7.1.0"
+        },
+        "process-timeout": 3600
     }
 }

phpunit.xml.dist

@@ -14,7 +14,6 @@
         stopOnFailure="false"
         stopOnIncomplete="false"
         stopOnSkipped="false"
-        syntaxCheck="true"
         timeoutForLargeTests="60"
         timeoutForMediumTests="10"
         timeoutForSmallTests="1"
@@ -35,7 +34,7 @@
     </testsuites>
     <filter>
         <whitelist>
-            <directory suffix=".php" processUncoveredFilesFromWhitelist="true">./src</directory>
+            <directory suffix=".php">./src</directory>
             <exclude>
                 <directory suffix=".php">./src/Exception</directory>
             </exclude>