Update build badge

Author: Kazuma TAKAOKA

README.md

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 # jdartsclone
 
-[![Build Status](https://travis-ci.org/WorksApplications/jdartsclone.svg?branch=develop)](https://travis-ci.org/WorksApplications/jdartsclone)
+[![Build](https://github.com/WorksApplications/jdartsclone/actions/workflows/build.yml/badge.svg)](https://github.com/WorksApplications/jdartsclone/actions/workflows/build.yml)
 
 jdartsclone is a port of the original Darts-clone to Java.
 Darts-clone is a library of TRIE structure using Double-Array.