Add tests and detect WhatsApp Web updates (#686)

* test setup, add initializer tests

* test sending messages

* add script to check latest version

* add github action

* use env vars

* configure environment with .env file

* add test for sticker name and author

* add DownloadManager model

* test chats and contacts

* test for number utility functions

* throw error if no remote id has been set

* Update .version

.eslintrc.json

@@ -5,7 +5,7 @@
         "es6": true,
         "node": true
     },
-    "extends": "eslint:recommended",
+    "extends": ["eslint:recommended", "plugin:mocha/recommended"],
     "globals": {
         "Atomics": "readonly",
         "SharedArrayBuffer": "readonly"
@@ -13,6 +13,7 @@
     "parserOptions": {
         "ecmaVersion": 2020
     },
+    "plugins": ["mocha"],
     "ignorePatterns": ["docs"],
     "rules": {
         "indent": [