fix(golang): handle github names with version in path

lib/datasource/go/index.js

@@ -15,9 +15,11 @@ async function getDatasource(name) {
     return { datasource: 'github', lookupName: `go-${pkg}/${pkg}` };
   }
   if (name.startsWith('github.com/')) {
+    const split = name.split('/');
+    const lookupName = split[1] + '/' + split[2];
     return {
       datasource: 'github',
-      lookupName: name.replace('github.com/', ''),
+      lookupName,
     };
   }
   const pkgUrl = `https://${name}?go-get=1`;