Update link to build status badge

Author: JermyTan

README.adoc

@@ -1,6 +1,7 @@
 = Address Book (Level 3)
 ifdef::env-github,env-browser[:relfileprefix: docs/]
-https://travis-ci.org/se-edu/addressbook-level3[image:https://travis-ci.org/se-edu/addressbook-level3.svg?branch=master[Build Status]]
+
+https://travis-ci.org/AY1920S1-CS2103T-F11-2/main[image:https://travis-ci.org/AY1920S1-CS2103T-F11-2/main.svg?branch=master[Build Status]]
 https://ci.appveyor.com/project/damithc/addressbook-level3[image:https://ci.appveyor.com/api/projects/status/3boko2x2vr5cc3w2?svg=true[Build status]]
 https://coveralls.io/github/se-edu/addressbook-level3?branch=master[image:https://coveralls.io/repos/github/se-edu/addressbook-level3/badge.svg?branch=master[Coverage Status]]
 https://www.codacy.com/app/damith/addressbook-level3?utm_source=github.com&utm_medium=referral&utm_content=se-edu/addressbook-level3&utm_campaign=Badge_Grade[image:https://api.codacy.com/project/badge/Grade/fc0b7775cf7f4fdeaf08776f3d8e364a[Codacy Badge]]