upgrade nextjs, preact, mdx-bundler, esbuild

lib/mdx.js

@@ -56,7 +56,8 @@ export async function getFileBySlug(type, slug) {
 
   // Parsing frontmatter here to pass it in as options to rehype plugin
   const { data: frontmatter } = matter(source)
-  const { code } = await bundleMDX(source, {
+  const { code } = await bundleMDX({
+    source,
     // mdx imports can be automatically source from the components directory
     cwd: path.join(root, 'components'),
     xdmOptions(options) {