Kubernetes version currency (#602)

+ Drop testing on 1.14 and 1.15
+ Add testing for 1.17 and 1.18
+ Change min suggested version from 1.10 to 1.14

Author: dgrove-oss

.travis.yml

@@ -23,10 +23,10 @@ env:
   - secure: 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
   - secure: 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
   matrix:
-    - TRAVIS_KUBE_VERSION=v1.14 OW_INCLUDE_SYSTEM_TESTS=true OW_CONTAINER_FACTORY=kubernetes
-    - TRAVIS_KUBE_VERSION=v1.14 OW_INCLUDE_SYSTEM_TESTS=false OW_CONTAINER_FACTORY=kubernetes OW_LEAN_MODE=true
-    - TRAVIS_KUBE_VERSION=v1.15 OW_INCLUDE_SYSTEM_TESTS=false OW_CONTAINER_FACTORY=kubernetes
-    - TRAVIS_KUBE_VERSION=v1.16 OW_INCLUDE_SYSTEM_TESTS=false OW_CONTAINER_FACTORY=kubernetes
+    - TRAVIS_KUBE_VERSION=v1.16 OW_INCLUDE_SYSTEM_TESTS=true OW_CONTAINER_FACTORY=kubernetes
+    - TRAVIS_KUBE_VERSION=v1.16 OW_INCLUDE_SYSTEM_TESTS=false OW_CONTAINER_FACTORY=kubernetes OW_LEAN_MODE=true
+    - TRAVIS_KUBE_VERSION=v1.17 OW_INCLUDE_SYSTEM_TESTS=false OW_CONTAINER_FACTORY=kubernetes
+    - TRAVIS_KUBE_VERSION=v1.18 OW_INCLUDE_SYSTEM_TESTS=false OW_CONTAINER_FACTORY=kubernetes
 
 services:
   - docker

docs/k8s-technical-requirements.md

@@ -21,8 +21,8 @@
 
 The Kubernetes cluster on which you are deploying OpenWhisk must meet
 the following requirements:
-* [Kubernetes](https://github.com/kubernetes/kubernetes) version 1.10+.
-  Our automated testing currently covers Kubernetes versions 1.14, 1.15 and 1.16.
+* [Kubernetes](https://github.com/kubernetes/kubernetes) version 1.14+.
+  Our automated testing currently covers Kubernetes versions 1.16, 1.17 and 1.18.
 * The ability to create Ingresses to make a Kubernetes service
   available outside of the cluster so you can actually use OpenWhisk.
 * Unless you disable persistence (see