Test against multiple k8s version (#19)

Signed-off-by: Tamal Saha <tamal@appscode.com>

Author: tamalsaha

.github/workflows/ci.yml

@@ -12,6 +12,9 @@ jobs:
   build:
     name: Build
     runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        k8s: [v1.12.10, v1.13.10, v1.14.6, v1.15.3, v1.16.2]
     steps:
 
     - name: Check out code into the Go module directory
@@ -23,11 +26,12 @@ jobs:
         sudo apt-get install -y bzr
         make ci
 
-    - name: Create Kubernetes cluster
+    - name: Create Kubernetes ${{ matrix.k8s }} cluster
       id: kind
       uses: engineerd/setup-kind@v0.1.0
       with:
         config: hack/kubernetes/kind.yaml
+        image: kindest/node:${{ matrix.k8s }}
 
     - name: Prepare cluster for testing
       id: local-path