Replace fetch with synchronize due to memory error (#5084)

Fix for Kubespray Issue #5059 (https://github.com/kubernetes-sigs/kubespray/issues/5059). There is a known issue with the 'fetch' module that will sometimes lead to it failing with a memory error. See ansible/ansible#11702 (https://github.com/ansible/ansible/issues/11702). I encountered this issue with the "Copy kubectl binary to ansible host" task in kubespray/roles/kubernetes/client/tasks/main.yml, and it caused my entire deployment to error out (see "Output of ansible run" above). Replacing 'fetch' with 'synchronize' fixes this issue.