Update to Bot API 5.0, add rake tasks for deleteWebhook, close & logOut

CHANGELOG.md

@@ -3,6 +3,7 @@
 - Add `:path` option to `telegram_webhook` route helper.
 - __Breaking change!__ Default route is generated using hashed bot token.
   Please reconfigure webhook after update (`rake telegram:bot:set_webhook`).
+- Update to Bot API 5.0, add rake tasks for `deleteWebhook`, `close` & `logOut`.
 
 # 0.14.4