feat(ec2): add c7gn instance type (#26905)

https://aws.amazon.com/about-aws/whats-new/2023/06/amazon-ec2-c7gn-instances-general-availability/

Spiritual successor of #23147

----

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

Author: robertd

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

@@ -494,6 +494,18 @@ export enum InstanceClass {
    */
   C6GN = 'c6gn',
 
+  /**
+   * Compute optimized instances for high performance computing, 7th generation with Graviton3 processors
+   * and high network bandwidth capabilities
+   */
+  COMPUTE7_GRAVITON3_HIGH_NETWORK_BANDWIDTH = 'compute7-graviton3-high-network-bandwidth',
+
+  /**
+   * Compute optimized instances for high performance computing, 7th generation with Graviton3 processors
+   * and high network bandwidth capabilities
+   */
+  C7GN = 'c7gn',
+
   /**
    * Storage-optimized instances, 2nd generation
    */
@@ -1219,6 +1231,8 @@ export class InstanceType {
       [InstanceClass.C7G]: 'c7g',
       [InstanceClass.COMPUTE7_GRAVITON3_NVME_DRIVE]: 'c7gd',
       [InstanceClass.C7GD]: 'c7gd',
+      [InstanceClass.COMPUTE7_GRAVITON3_HIGH_NETWORK_BANDWIDTH]: 'c7gn',
+      [InstanceClass.C7GN]: 'c7gn',
       [InstanceClass.STORAGE2]: 'd2',
       [InstanceClass.D2]: 'd2',
       [InstanceClass.STORAGE3]: 'd3',