Do not stay in GitHub workspace to not have Gemfile conflict

If the current project is a Ruby one, the Docker image's Ruby version can
diverge from the Gemfile one. By staying in another folder, we'll avoid
this kind of situation.

Author: scharrier

entrypoint.sh

@@ -1,4 +1,5 @@
 #!/bin/sh -l
 
+cd /home
 gem install bump-cli
 $GEM_HOME/bin/bump $1 ${GITHUB_WORKSPACE}/$2 --id $3 --token $4 --validation $5