chore: upgrade ESLint to v9 and update configurations (#356)

* chore: upgrade ESLint to v9 and update configurations

Upgrade ESLint and configure and update ESLint rules.

* refactor: update code to comply with new ESLint v9 rules

.prettierignore

@@ -9,5 +9,5 @@
 !astro.config.ts
 !package.json
 !.prettierrc
-!.eslintrc.js
+!eslint.config.mjs
 !README.md

eslint.config.mjs

@@ -0,0 +1,44 @@
+import js from "@eslint/js";
+import globals from "globals";
+import tseslint from "typescript-eslint";
+import astroParser from "astro-eslint-parser";
+import eslintPluginAstro from "eslint-plugin-astro";
+
+export default [
+  js.configs.recommended,
+  ...tseslint.configs.recommended,
+  ...eslintPluginAstro.configs.recommended,
+  {
+    languageOptions: {
+      globals: {
+        ...globals.browser,
+        ...globals.node,
+      },
+    },
+  },
+  {
+    files: ["*.astro"],
+    languageOptions: {
+      parser: astroParser,
+      parserOptions: {
+        parser: "@typescript-eslint/parser",
+        extraFileExtensions: [".astro"],
+      },
+    },
+  },
+  {
+    files: ["tailwind.config.cjs", "**/*.d.ts"],
+    rules: {
+      "@typescript-eslint/no-require-imports": "off",
+      "@typescript-eslint/triple-slash-reference": "off",
+    },
+  },
+  {
+    rules: {
+      "@typescript-eslint/no-unused-expressions": "off",
+    },
+  },
+  {
+    ignores: ["dist/**", ".astro"],
+  },
+];