feat(ec2): allow the use of graviton3 processors (aws#20541)

feat: allow the use of graviton3, 7th generation processors

fixes: aws#20482

----

### All Submissions:

* [x] Have you followed the guidelines in our [Contributing guide?](https://github.com/aws/aws-cdk/blob/master/CONTRIBUTING.md)

### Adding new Unconventional Dependencies:

* [ ] This PR adds new unconventional dependencies following the process described [here](https://github.com/aws/aws-cdk/blob/master/CONTRIBUTING.md/#adding-new-unconventional-dependencies)

### New Features

* [x] Have you added the new feature to an [integration test](https://github.com/aws/aws-cdk/blob/master/INTEGRATION_TESTS.md)?
	* [x] Did you use `yarn integ` to deploy the infrastructure and generate the snapshot (i.e. `yarn integ` without `--dry-run`)?

*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-ec2/README.md

@@ -962,6 +962,16 @@ new ec2.Instance(this, 'Instance4', {
     generation: ec2.AmazonLinuxGeneration.AMAZON_LINUX_2022,
   }),
 });
+
+// Graviton 3 Processor
+new ec2.Instance(this, 'Instance5', {
+  vpc,
+  instanceType: ec2.InstanceType.of(ec2.InstanceClass.C7G, ec2.InstanceSize.LARGE),
+  machineImage: new ec2.AmazonLinuxImage({
+    generation: ec2.AmazonLinuxGeneration.AMAZON_LINUX_2,
+    cpuType: ec2.AmazonLinuxCpuType.ARM_64,
+  }),
+});
 ```
 
 ### Configuring Instances using CloudFormation Init (cfn-init)

packages/@aws-cdk/aws-ec2/lib/instance-types.ts

@@ -368,6 +368,16 @@ export enum InstanceClass {
    */
   C6G = 'c6g',
 
+  /**
+   * Compute optimized instances for high performance computing, 7th generation with Graviton3 processors
+   */
+  COMPUTE7_GRAVITON3 = 'c7g',
+
+  /**
+   * Compute optimized instances for high performance computing, 7th generation with Graviton3 processors
+   */
+  C7G = 'c7g',
+
   /**
    * Compute optimized instances for high performance computing, 6th generation with Graviton2 processors
    * and local NVME drive