Update symfony/css-selector to "^4.0 || ^5.0". Closes #26 Closes #27

Author: Andrew Scott

composer.json

@@ -16,7 +16,7 @@
         "ext-mbstring": "*",
         "ext-libxml": "*",
         "lib-libxml": ">=2.7.7",
-        "symfony/css-selector": "^4.0"
+        "symfony/css-selector": "^4.0 || ^5.0"
     },
     "require-dev": {
         "phpunit/phpunit": "^7.0",