Bump composer dependencies

composer.json

@@ -11,13 +11,13 @@
     ],
     "require": {
         "guzzlehttp/guzzle": "^6.3|^7.0",
-        "PHP": "^7.1|^8.0",
+        "PHP": "^7.2|^8.0",
         "kornrunner/keccak": "~1.0",
-        "phpseclib/phpseclib": "~2.0.11",
+        "phpseclib/phpseclib": "~2.0.30",
         "ext-mbstring": "*"
     },
     "require-dev": {
-        "phpunit/phpunit": "~6.0|~8.0"
+        "phpunit/phpunit": "~8.0|~9.0"
     },
     "autoload": {
         "psr-4": {

phpunit.xml

@@ -7,8 +7,7 @@
          convertNoticesToExceptions="true"
          convertWarningsToExceptions="true"
          processIsolation="false"
-         stopOnFailure="false"
-         syntaxCheck="false">
+         stopOnFailure="false">
 
     <testsuite name="Web3.php unit test">
         <directory suffix="Test.php">./test/unit</directory>