Remove obsolete Travis CI config

Also restore .mailmap, erroneously deleted in
commit bed854c1daeb7408f861ec49fc3fb30770e1c49a

Change-Id: I086f83a46d5074024258d246b29dc232a79c74de
diff --git a/AUTHORS.md b/AUTHORS.md
index 0c40c8d..72c3674 100644
--- a/AUTHORS.md
+++ b/AUTHORS.md
@@ -12,7 +12,7 @@
 * Md Ashiqur Rahman <https://ashiqrahman.com>
 * Junxiao Shi <https://cs.arizona.edu/~shijunxiao>
 * Yufeng Zhang <https://yufengzh.io>
-* ***(Maintainer)*** Zhiyi Zhang <https://zhiyi-zhang.com>
+* Zhiyi Zhang <https://zhiyi-zhang.com>
 
 # Technical Advisors