fix: include type definitions to files array

Author: SomedayIsTheDay

package.json

@@ -24,7 +24,8 @@
   "files": [
     "lib",
     "bundle.js",
-    "whatsapp-api-client.min.js"
+    "whatsapp-api-client.min.js",
+    "src/index.d.ts"
   ],
   "keywords": [
     "whatsapp",