End-to-end tests: Automatically update dependencies of the CDK apps created by end-to-end tests

[madeline-k]

The end-to-end tests create an entire functioning CDK app for each test to execute CDK commands on. The dependencies for those apps are defined in tests/end-to-end/app-boilerplate-files. We should have a mechanism to auto-update these so that the tests are always using the most recent version of the CDK.