AC-1059: Move PHPCompatibility rules from Magento tests

Author: svera

Magento2/ruleset.xml

@@ -738,3 +738,9 @@
         <severity>0</severity>
     </rule>
 </ruleset>
+<ruleset name="PHPCompatibilityMagento">
+    <description>Magento 2 specific ruleset which checks for PHP cross version compatibility.</description>
+    <rule ref="PHPCompatibility">
+        <exclude name="PHPCompatibility.Miscellaneous.RemovedAlternativePHPTags.MaybeASPOpenTagFound" />
+    </rule>
+</ruleset>

composer.json

@@ -12,7 +12,8 @@
         "squizlabs/php_codesniffer": "^3.6",
         "webonyx/graphql-php": "^14.9",
         "ext-simplexml": "*",
-        "ext-dom": "*"
+        "ext-dom": "*",
+        "phpcompatibility/php-compatibility": "^9.3"
     },
     "require-dev": {
         "phpunit/phpunit": "^9.5.8"