feat(doc): update expired infos

  1. update gitter badges
  2. remove travis-ci badges
  3. update Telegram link

Author: halibobo1205

README.md

@@ -12,11 +12,7 @@
 
 <p align="center">
   <a href="https://gitter.im/tronprotocol/allcoredev">
-    <img src="https://camo.githubusercontent.com/da2edb525cde1455a622c58c0effc3a90b9a181c/68747470733a2f2f6261646765732e6769747465722e696d2f4a6f696e253230436861742e737667">
-  </a>
-
-  <a href="https://travis-ci.org/tronprotocol/java-tron">
-    <img src="https://travis-ci.org/tronprotocol/java-tron.svg?branch=develop">
+    <img src="https://img.shields.io/gitter/room/tronprotocol/java-tron.svg">
   </a>
 
   <a href="https://codecov.io/gh/tronprotocol/java-tron">
@@ -173,7 +169,7 @@ This will mount the `output-directory` and `logs` directories on the host, the d
 
 [Tron Developers & SRs](https://discord.gg/hqKvyAM) is Tron's official Discord channel. Feel free to join this channel if you have any questions.
 
-[Core Devs Community](https://t.me/troncoredevscommunity) is the Telegram channel for java-tron community developers. If you want to contribute to java-tron, please join this channel.
+[Telegram Community](https://t.me/TronOfficialDevelopersGroupEn) is the Telegram channel for java-tron community developers. If you want to contribute to java-tron, please join this channel.
 
 [tronprotocol/allcoredev](https://gitter.im/tronprotocol/allcoredev) is the official Gitter channel for developers.