Fix default permissions of install_helm.sh
At the moment, continuousintegration/ci_helpers/install_helm.sh has access permissions 644, which do not allow it to be executed. It should be 755 like the other scripts in the same directory.
At the moment, continuousintegration/ci_helpers/install_helm.sh has access permissions 644, which do not allow it to be executed. It should be 755 like the other scripts in the same directory.