Minor post fixes. Makes posts publishable with a date

src/content.config.ts

@@ -10,7 +10,8 @@ const blog = defineCollection({
       title: z.string(),
       description: z.string(),
       // Transform string to Date object
-      pubDate: z.coerce.date(),
+      // Presence of this value indicates that the post is published
+      pubDate: z.coerce.date().optional(),
       updatedDate: z.coerce.date().optional(),
       heroImage: image().optional(),
     }),