feat(ec2): trn1 instance type (aws#28477)

adding support of trn1 instance type
they were introduced [here](https://aws.amazon.com/ec2/instance-types/trn1/)

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

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

@@ -611,6 +611,11 @@ export enum InstanceClass {
    */
   STORAGE_COMPUTE_1 = 'storage-compute-1',
 
+  /**
+   * High performance computing powered by AWS Trainium
+   */
+  TRN1 = 'trn1',
+
   /**
    * Storage/compute balanced instances, 1st generation
    */
@@ -1395,6 +1400,7 @@ export class InstanceType {
       [InstanceClass.D3]: 'd3',
       [InstanceClass.STORAGE3_ENHANCED_NETWORK]: 'd3en',
       [InstanceClass.D3EN]: 'd3en',
+      [InstanceClass.TRN1]: 'trn1',
       [InstanceClass.STORAGE_COMPUTE_1]: 'h1',
       [InstanceClass.H1]: 'h1',
       [InstanceClass.IO3]: 'i3',