Use readme.md as main readme

Author: pfefferle

.github/workflows/update-assets.yml

@@ -15,3 +15,4 @@ jobs:
         SVN_PASSWORD: ${{ secrets.SVN_PASSWORD }}
         SVN_USERNAME: ${{ secrets.SVN_USERNAME }}
         SLUG: webmention
+        README_NAME: readme.md

Gruntfile.js

@@ -3,10 +3,6 @@
   "description": "Webmention support for WordPress posts",
   "main": "webmention.php",
   "devDependencies": {
-    "grunt": "^1.6.1",
-    "grunt-checktextdomain": "^1.0.1",
-    "grunt-wp-i18n": "^1.0.3",
-    "grunt-wp-readme-to-markdown": "^2.1.0"
   },
   "repository": {
     "type": "git",