chore(ecs): add test and docs for using ARM instances (aws#14536)

Closes aws#14433


----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

packages/@aws-cdk/aws-ecs/README.md

@@ -153,6 +153,22 @@ cluster.addCapacity('bottlerocket-asg', {
 });
 ```
 
+### ARM64 (Graviton) Instances
+
+To launch instances with ARM64 hardware, you can use the Amazon ECS-optimized
+Amazon Linux 2 (arm64) AMI. Based on Amazon Linux 2, this AMI is recommended
+for use when launching your EC2 instances that are powered by Arm-based AWS
+Graviton Processors.
+
+```ts
+cluster.addCapacity('graviton-cluster', {
+  minCapacity: 2,
+  instanceType: new ec2.InstanceType('c6g.large'),
+  machineImage: ecs.EcsOptimizedImage.amazonLinux2(ecs.AmiHardwareType.ARM),
+});
+
+```
+
 ### Spot Instances
 
 To add spot instances into the cluster, you must specify the `spotPrice` in the `ecs.AddCapacityOptions` and optionally enable the `spotInstanceDraining` property.

packages/@aws-cdk/aws-ecs/lib/cluster.ts

@@ -466,7 +466,7 @@ export enum WindowsOptimizedVersion {
 /*
  * TODO:v2.0.0
  *  * remove `export` keyword
- *  * remove @depracted
+ *  * remove @deprecated
  */
 /**
  * The properties that define which ECS-optimized AMI is used.

packages/@aws-cdk/aws-ecs/test/ecs-cluster.test.ts → packages/@aws-cdk/aws-ecs/test/cluster.test.ts

@@ -990,6 +990,17 @@ nodeunitShim({
     test.done();
   },
 
+  'allows returning the correct image for linux 2 for EcsOptimizedImage with ARM hardware'(test: Test) {
+    // GIVEN
+    const stack = new cdk.Stack();
+
+    test.equal(ecs.EcsOptimizedImage.amazonLinux2(ecs.AmiHardwareType.ARM).getImage(stack).osType,
+      ec2.OperatingSystemType.LINUX);
+
+    test.done();
+  },
+
+
   'allows returning the correct image for windows for EcsOptimizedImage'(test: Test) {
     // GIVEN
     const stack = new cdk.Stack();