Fix for deprecated field

Author: cblanc

docusaurus.config.ts

@@ -20,7 +20,12 @@ const config: Config = {
   projectName: "postcodes.io", // Usually your repo name.
 
   onBrokenLinks: "throw",
-  onBrokenMarkdownLinks: "warn",
+
+  markdown: {
+    hooks: {
+      onBrokenMarkdownLinks: "warn",
+    },
+  },
 
   // Even if you don't use internationalization, you can use this field to set
   // useful metadata like html lang. For example, if your site is Chinese, you
@@ -35,7 +40,7 @@ const config: Config = {
       "classic",
       {
         docs: {
-          sidebarPath: require.resolve("./sidebars"),
+          sidebarPath: "./sidebars.ts",
           docItemComponent: "@theme/ApiItem", // Fix for docusaurus-openapi-docs
         },
         theme: {