Security Fixes

• Bump k3s to v1.17.6+k3s1 #505
  • CVE-2020-10749 - IPv4 only clusters susceptible to MitM attacks via IPv6 rogue router advertisements
  • CVE-2020-8555 - kube-controller-manager SSRF

Bug Fixes

• Establish /usr/libexec/kubernetes symlink to persistent disk #447 (thanks @zimme)
  This makes the FlexVolume plugin happy.