rename typescript definition file

Author: koddsson

task-lists-element.d.ts renamed to index.d.ts

@@ -5,7 +5,7 @@
   "repository": "github/task-lists-element",
   "main": "dist/index.umd.js",
   "module": "dist/index.esm.js",
-  "types": "task-lists-element.d.ts",
+  "types": "index.d.ts",
   "scripts": {
     "clean": "rm -rf dist",
     "lint": "github-lint",
@@ -22,7 +22,7 @@
   "license": "MIT",
   "files": [
     "dist",
-    "task-lists-element.d.ts"
+    "index.d.ts"
   ],
   "devDependencies": {
     "@babel/core": "^7.4.5",