v1.51.0

Features

• cloudfront: Add connectionAttempts, connectionTimeout in origin configuration (#8573) (84b923f), closes #8572
• Developer Preview of CDK Pipelines (#8868) (d2609bd), closes aws/aws-cdk-rfcs#49

Bug Fixes

• appmesh: Update enums for appmesh (#8716) (64e3d88)
• cli: Python sample app template does not follow PEP8 (#8936) (0717919)
• codepipeline: set correct header assignment in S3 deployment cache control (#8864) (be1094b), closes #8774
• ec2: VpcEndpoint AZ lookup fails for AWS services (#8386) (54e5c36)
• iam: cannot import service role with a principal in its path (#8692) (55eb7d7), closes #8691