feat: add ts types

Author: zirkelc

package.json

@@ -15,6 +15,7 @@
     "iot"
   ],
   "main": "lib/serverless.js",
+  "types": "types/index.d.ts",
   "bin": {
     "serverless": "./bin/serverless.js",
     "sls": "./bin/serverless.js"
@@ -189,4 +190,4 @@
     "node": ">=12.0"
   },
   "license": "MIT"
-}
+}