v0.7.1

CHANGELOG

• [GH-51] Make shell scripts more portable (@Jayed)
• [GH-53] Use generated kube_config_cluster.yml when updating cluster (@yamamoto-febc)
• [GH-54] Rename from Makefile to GNUmakefile (@yamamoto-febc)
• [GH-55] Use CustomizeDiff func for recompute rke_cluster_yaml (@yamamoto-febc)