Add single_version config to fix URLs.

Fixes #14

preview/README.md

@@ -56,3 +56,4 @@ These are all the parameters this action supports:
 * `message-template` (_optional_): Text message to be injected by the action in the Pull Request description. It supports the following placeholders to be replaced:
   * `{docs-pr-index-url}`: URL to the root of the documentation for the Pull Request preview.
 * `platform` (_optional_): Read the Docs Community (`community`) or Read the Docs for Business (`business`). (default: `community`)
+* `single_version` (_optional_): Set this to `'true'` if your project is single version, so we can link to the correct URL. (default: `false`)

preview/action.yaml

@@ -24,6 +24,10 @@ inputs:
     description: "Read the Docs Community or Read the Docs for Business (community or business)"
     default: "community"
     required: false
+  single_version:
+    description: "Site is a single verison project, so link to the top level."
+    default: 'false' 
+    required: false
 
 runs:
   using: "composite"

preview/scripts/edit-description.js

@@ -9,7 +9,12 @@ module.exports = async ({inputs, github, context}) => {
     if (RTD_PLATFORM == "business") {
         var RTD_DOMAIN = "com.readthedocs.build";
     }
-    var RTD_URL = `https://${RTD_PROJECT_SLUG}--${PR_NUMBER}.${RTD_DOMAIN}/${RTD_PROJECT_LANGUAGE}/${PR_NUMBER}/`;
+    var RTD_DOMAIN = `https://${RTD_PROJECT_SLUG}--${PR_NUMBER}.${RTD_DOMAIN}/`;
+    if (RTD_SINGLE_VERSION == "true") {
+        RTD_URL = RTD_DOMAIN + `${RTD_PROJECT_LANGUAGE}/${PR_NUMBER}/`;
+    } else {
+        RTD_URL = RTD_DOMAIN; 
+    }
 
     var MESSAGE_SEPARATOR_START = `\r\n\r\n<!-- readthedocs-preview ${RTD_PROJECT_SLUG} start -->\r\n`;
     var MESSAGE_SEPARATOR_END = `\r\n<!-- readthedocs-preview ${RTD_PROJECT_SLUG} end -->`;