docs: correct code example in README of aws-cdk-lib/pipelines (#33354)

The code example in question mixed us-west-1 and us-east-1 in the same resource, which does not make sense and may be confusing.

Replace mentions of us-east-1 with us-west-1.

### Issue # (if applicable)

Closes #<issue number here>.

### Reason for this change

I was reading through the CDK docs for the pipeline constructs and I saw this typo in the code example, so I wanted to get it fixed.

### Description of changes

I edited a code example in a README file to correct a documentation inconsistency.

### Describe any new or updated permissions being added

N/A


### Description of how you validated changes

N/A. No changes to functional components.

### Checklist
- [X] My code adheres to the [CONTRIBUTING GUIDE](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md) and [DESIGN GUIDELINES](https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md)

----

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

Author: joaonmatos

packages/aws-cdk-lib/pipelines/README.md

@@ -1299,11 +1299,11 @@ declare const sharedXRegionUsWest1KeyArn: string;
 declare const sharedXRegionUsWest2BucketArn: string;
 declare const sharedXRegionUsWest2KeyArn: string;
 
-const usWest1Bucket = s3.Bucket.fromBucketAttributes(scope, 'UsEast1Bucket', {
+const usWest1Bucket = s3.Bucket.fromBucketAttributes(scope, 'UsWest1Bucket', {
   bucketArn: sharedXRegionUsWest1BucketArn,
   encryptionKey: kms.Key.fromKeyArn(
     scope,
-    'UsEast1BucketKeyArn',
+    'UsWest1BucketKeyArn',
     sharedXRegionUsWest1BucketArn
   ),
 });