Update eleventy to 3.0.0-alpha.4

package.json

@@ -3,6 +3,7 @@
   "version": "1.0.0",
   "description": "",
   "main": "index.js",
+  "type": "module",
   "scripts": {
     "test": "echo \"Error: no test specified\" && exit 1",
     "build:eleventy": "eleventy --input=src/",
@@ -17,7 +18,7 @@
   "author": "",
   "license": "ISC",
   "dependencies": {
-    "@11ty/eleventy": "^2.0.1",
+    "@11ty/eleventy": "3.0.0-alpha.5",
     "@11ty/eleventy-fetch": "^4.0.0",
     "@11ty/eleventy-plugin-rss": "^1.2.0",
     "@11ty/eleventy-plugin-syntaxhighlight": "^4.2.0",
@@ -31,7 +32,7 @@
     "markdown-it-abbr": "^1.0.4",
     "markdown-it-anchor": "^8.6.7",
     "markdown-it-footnote": "^3.0.3",
-    "postcss": "^8.4.33",
+    "postcss": "^8.4.35",
     "postcss-cli": "^10.1.0",
     "seedrandom": "^3.0.5"
   }