Bump version to 3.1
Bump version to 3.1

codilime/cloudify-system-tests,cloudify-cosmo/cloudify-system-tests,isaac-s/cloudify-system-tests,isaac-s/cloudify-system-tests,cloudify-cosmo/cloudify-system-tests,codilime/cloudify-system-tests,codilime/cloudify-system-tests,isaac-s/cloudify-system-tests