Remove release notes section from README
Remove release notes section from README

Release notes will go in a CHANGELOG.md file, separate from the README.

Change-Id: I04a6dd1f5cf0b711b32fef0ad8da57cf6c86434a

openstack/puppet-openstack-cookiecutter,openstack/puppet-openstack-cookiecutter,openstack/puppet-openstack-cookiecutter