Update build status badge link in README

Author: jakoch

README.adoc

@@ -1,6 +1,6 @@
 # Fifengine - Documentations
 
-image:https://travis-ci.org/fifengine/fifengine-docs.svg["Build Status", link="https://travis-ci.org/fifengine/fifengine-docs"]
+image:https://github.com/fifengine/fifengine-docs/actions/workflows/build-docs.yml/badge.svg?branch=master["Build Status", link="https://github.com/fifengine/fifengine-docs"]
 
 :USR-MAN-HTML-EN:   https://fifengine.github.io/fifengine-docs/user-manual/en/[EN]
 :DEV-MAN-HTML-EN:   https://fifengine.github.io/fifengine-docs/developer-manual/en/[EN]
@@ -31,4 +31,4 @@ image:https://travis-ci.org/fifengine/fifengine-docs.svg["Build Status", link="h
 | C++ API Documentation    | HTML     | https://fifengine.github.io/fifechan/api/
 | Website (Github Pages)   | HTML     | https://fifengine.github.io/fifechan/
 | Docs Repository          | ASCIIDOC | https://github.com/fifengine/fifechan/tree/main/docs
-|====================
+|====================