Allow newer deps

Author: dvdoug

composer.json

@@ -26,7 +26,7 @@
     ],
     "require": {
         "php": ">=7.1",
-        "phpunit/php-code-coverage": "^6.0",
+        "phpunit/php-code-coverage": "^6.0||^7.0",
         "behat/behat": "^3.5",
         "guzzlehttp/guzzle": "^6.0",
         "symfony/config": "^3.4||^4.0",
@@ -36,7 +36,7 @@
         "symfony/http-foundation": "^3.4||^4.0"
     },
     "require-dev": {
-        "phpunit/phpunit": "^7.0",
+        "phpunit/phpunit": "^7.0||^8.0",
         "mikey179/vfsstream": "^1.6",
         "friendsofphp/php-cs-fixer": "^2.13"
     },