Add typescript definition (#40)

Author: joshuajaco

lib/index.d.ts

@@ -0,0 +1,12 @@
+import type { ESLint, Linter } from "eslint";
+
+declare const plugin: ESLint.Plugin & {
+  configs: {
+    recommended: ESLint.ConfigData;
+    all: ESLint.ConfigData;
+    "flat/recommended": Linter.Config;
+    "flat/all": Linter.Config;
+  };
+};
+
+export = plugin;

package.json

@@ -21,6 +21,7 @@
   "license": "MIT",
   "exports": "./lib/index.js",
   "main": "lib/index.js",
+  "types": "lib/index.d.ts",
   "files": [
     "lib/",
     "CHANGELOG.md"