chore: renames .eleventy.js to index.js

Author: saneef

.eleventy.js index.js.eleventy.js renamed to index.js

@@ -2,7 +2,7 @@
   "name": "eleventy-plugin-asciidoc",
   "version": "5.0.0-alpha.1",
   "description": "Adds support for AsciiDoc to Eleventy",
-  "main": ".eleventy.js",
+  "main": "index.js",
   "funding": "https://github.com/sponsors/saneef/",
   "repository": {
     "type": "git",