Set canonical URL to corresponding proprietary docs at getambassador.io

The proprietary documentation is very similar, so this is done to become
more SEO friendly.

Signed-off-by: Thomas Hallgren <thomas@tada.se>

docs-config.js

@@ -39,7 +39,8 @@ module.exports = {
   },
 
   canonicalURL: function(node) {
-    return this.urlpath(node);
+    const relpath =  this.urlpath(node).split(path.posix.sep).slice(3).join(path.posix.sep);
+    return `https://www.getambassador.io/docs/telepresence/latest/${relpath}`;
   },
 
   githubURL: function(node) {

src/components/EasyLayout/index.js

@@ -25,7 +25,7 @@ export default function EasyLayout({
     <Layout location={location}>
       <Helmet>
         <title>{title} | {data.site.siteMetadata.title}</title>
-        <link rel="canonical" href={`${data.site.siteMetadata.siteURL}${location.pathname}`} />
+        <link rel="canonical" href={`https://www.getambassador.io/docs/telepresence${location.pathname}`} />
         { description && <meta name="description" content={description} /> }
       </Helmet>
       {children}