README: git no longer needed for hello-ci-lite, as CxxTest is not used

README.md

-Hello CI
-========
+Hello CI lite
+=============
 [![Build Status](http://137.226.248.58/api/badges/ywashio/hello-ci/status.svg)](http://137.226.248.58/ywashio/hello-ci)
 
 Let's say hello to CI (represented by drone resp. GitLab Runner), here trimmed trimmed down to the essentials!
@@ -15,7 +15,6 @@ make
 
 * make
 * g++
-* git (to update submodule cxxtest)
 
 # Testing