update social media image

Author: Khoubza Younes

_includes/head.html

@@ -6,7 +6,9 @@
     <meta name="description" content="{{ site.data.project.description }}"/>
 {% endif %}
 
+<meta property="og:image" content="/dist/images/php-flasher-logo.png">
 {% seo %}
+<meta property="og:image" content="/dist/images/php-flasher-logo.png">
 
 <link rel="icon" type="image/png" href="/dist/images/favicon.ico"/>
 <link rel="apple-touch-icon" sizes="180x180" href="/dist/images/apple-touch-icon.png">