Merge pull request #462 from edgarsherman/fix/php8deprecations

fix: some php8 deprecation errors

Author: sujitharamadass

composer.json

@@ -10,7 +10,9 @@
         "ext-dom": "*"
     },
     "require-dev": {
-        "phpunit/phpunit": "^5.0 || ^6.0 || ^7.0"
+        "phpunit/phpunit": "^5.0 || ^6.0 || ^7.0 || ^8",
+        "php-mock/php-mock-phpunit": "^2.6",
+        "php-mock/php-mock": "^2.3"
     },
     "autoload": {
         "psr-4": {