Migrate to Svelte 4

.eslintrc.cjs

@@ -1,16 +1,25 @@
 module.exports = {
   root: true,
   parser: '@typescript-eslint/parser',
-  extends: ['eslint:recommended', 'plugin:@typescript-eslint/recommended', 'prettier'],
-  plugins: ['svelte3', '@typescript-eslint'],
+  extends: ['plugin:svelte/recommended', 'plugin:@typescript-eslint/recommended', 'prettier'],
+  plugins: ['@typescript-eslint'],
   ignorePatterns: ['*.cjs'],
-  overrides: [{ files: ['*.svelte'], processor: 'svelte3/svelte3' }],
+  overrides: [
+    {
+      files: ['*.svelte'],
+      parser: 'svelte-eslint-parser',
+      parserOptions: {
+        parser: '@typescript-eslint/parser'
+      }
+    }
+  ],
   settings: {
     'svelte3/typescript': () => require('typescript')
   },
   parserOptions: {
     sourceType: 'module',
-    ecmaVersion: 2020
+    ecmaVersion: 2020,
+    extraFileExtensions: ['.svelte']
   },
   env: {
     browser: true,