chore(cdk): use RegionInfo instead of aws-sdk v2 for region domain suffix

packages/aws-cdk/lib/api/aws-auth/sdk.ts

@@ -1,3 +1,4 @@
+import * as region_info from '@aws-cdk/region-info';
 import * as AWS from 'aws-sdk';
 import type { ConfigurationOptions } from 'aws-sdk/lib/config-base';
 import { debug, trace } from './_env';
@@ -6,21 +7,10 @@ import { cached } from './cached';
 import { Account } from './sdk-provider';
 import { traceMethods } from '../../util/tracing';
 
-// We need to map regions to domain suffixes, and the SDK already has a function to do this.
-// It's not part of the public API, but it's also unlikely to go away.
-//
-// Reuse that function, and add a safety check, so we don't accidentally break if they ever
-// refactor that away.
-
 /* eslint-disable @typescript-eslint/no-require-imports */
-const regionUtil = require('aws-sdk/lib/region_config');
 require('aws-sdk/lib/maintenance_mode_message').suppress = true;
 /* eslint-enable @typescript-eslint/no-require-imports */
 
-if (!regionUtil.getEndpointSuffix) {
-  throw new Error('This version of AWS SDK for JS does not have the \'getEndpointSuffix\' function!');
-}
-
 export interface ISDK {
   /**
    * The region this SDK has been instantiated for
@@ -291,7 +281,11 @@ export class SDK implements ISDK {
   }
 
   public getEndpointSuffix(region: string): string {
-    return regionUtil.getEndpointSuffix(region);
+    const suffix = region_info.RegionInfo.get(region).domainSuffix;
+    if (!suffix) {
+      throw new Error(`Could not find domainSuffix in RegionInfo for ${region}`);
+    }
+    return suffix;
   }
 
   /**