fix(typescript/eks): compile fails for missing property 'version' (aw…

…s-samples#315)

This is due to the breaking change in the eks module introduced in
version 1.50.0.
https://github.com/aws/aws-cdk/blob/master/CHANGELOG.md#1500-2020-07-07

.gitignore

@@ -377,5 +377,6 @@ $RECYCLE.BIN/
 *.swp
 cdk.context.json
 package-lock.json
+yarn.lock
 .cdk.staging
 cdk.out

typescript/eks/cluster/index.ts

@@ -18,7 +18,8 @@ class EKSCluster extends cdk.Stack {
     const eksCluster = new eks.Cluster(this, 'Cluster', {
       vpc: vpc,
       kubectlEnabled: true,  // we want to be able to manage k8s resources using CDK
-      defaultCapacity: 0  // we want to manage capacity our selves
+      defaultCapacity: 0,  // we want to manage capacity our selves
+      version: eks.KubernetesVersion.V1_16,
     });
 
     const onDemandASG = new autoscaling.AutoScalingGroup(this, 'OnDemandASG', {