commit lock file for PetAdoptions/cdk/pet_stack

[odanado]

The lock file does not exist in PetAdoptions/cdk/pet_stack, resulting in a version inconsistency.
reproduction procedure:

$ cd PetAdoptions/cdk/pet_stack
$ npm install
$ npm run cdk bootstrap
This CDK CLI is not compatible with the CDK library used by your application. Please upgrade the CLI to the latest version.
(Cloud assembly schema version mismatch: Maximum schema version supported is 4.0.0, but found 5.0.0)

[awsimaya]

Cleaned up recently. Should be fixed now.