Add basic typescript declarations

package.json

@@ -1,6 +1,6 @@
 {
   "name": "maska",
-  "version": "1.3.1",
+  "version": "1.3.2",
   "description": "Simple zero-dependency input mask for Vue.js and vanilla JS",
   "keywords": [
     "mask",
@@ -25,6 +25,7 @@
   "module": "dist/maska.esm.js",
   "unpkg": "dist/maska.umd.js",
   "jsdelivr": "dist/maska.umd.js",
+  "types": "types/index.d.ts",
   "devDependencies": {
     "@babel/core": "^7.7.5",
     "@babel/preset-env": "^7.7.5",
@@ -34,7 +35,8 @@
     "rollup": "^2.0.2",
     "rollup-plugin-babel": "^4.4.0",
     "rollup-plugin-terser": "^7.0.0",
-    "standard": "^14.3.1"
+    "standard": "^14.3.1",
+    "typescript": "^4.1.2"
   },
   "browserslist": "> 0.25%, ie 11",
   "babel": {