docs(README): siteUrl option remove trailing slash

Author: stevensacks

README.md

@@ -69,7 +69,7 @@ plugins: [
       languages: [`en`, `es`, `de`],
       defaultLanguage: `en`,
       // if you are using Helmet, you must include siteUrl, and make sure you add http:https
-      siteUrl: `https://example.com/`,
+      siteUrl: `https://example.com`,
       // if you are using trailingSlash gatsby config include it here, as well (the default is 'always')
       trailingSlash: 'always',
       // you can pass any i18next options