Update to rke 0.2.7

This will also update k8s from v1.13.5-rancher1-3 to v1.14.3-rancher1-1.

Closes #246

ansible/group_vars/all/oas.yml

@@ -33,7 +33,8 @@ krew:
   sha256: 'dc2f2e1ec8a0acb6f3e23580d4a8b38c44823e948c40342e13ff6e8e12edb15a'
 
 rke:
-  version: '0.2.4'
+  # https://github.com/rancher/rke/releases
+  version: '0.2.7'
   # Also possible:
   # checksum: 'sha256:https://github.com/rancher/rke/releases/download/v0.2.4/sha256sum.txt'
-  checksum: 'sha256:d6d78f324fa5d86b42307e81b76c82881a7bc18fa29362af7026d541b948d56d'
+  checksum: 'sha256:7c05727aa3d6f8c4b5f60b057f1fe7883af48d5a778e3b1668f178dda84883ee'