Add og:image to cover.jpg

Author: marcelo-earth

public/index.html

@@ -15,6 +15,7 @@
       user's mobile device or desktop. See https://developers.google.com/web/fundamentals/web-app-manifest/
     -->
     <link rel="manifest" href="%PUBLIC_URL%/manifest.json" />
+    <meta name="og:image" content="%PUBLIC_URL%/cover.jpg" />
     <!--
       Notice the use of %PUBLIC_URL% in the tags above.
       It will be replaced with the URL of the `public` folder during the build.