update php copy (#193)

Author: shuangela

source/languages/php.txt

@@ -114,7 +114,7 @@ More Ways to Learn
       PHP Resources  →
 
    .. card::
-      :headline: PHP Developer Path
+      :headline: Learn about PHP and MongoDB
       :url: https://learn.mongodb.com/learning-paths/mongodb-php-developer-path
       :icon: /images/icons/university.svg
       :icon-alt: Learn icon