chore(deps): bump @aws-cdk/toolkit-lib

Bumps the aws-cdk group with 1 update in the / directory: [@aws-cdk/toolkit-lib](https://github.com/aws/aws-cdk-cli/tree/HEAD/packages/@aws-cdk/toolkit-lib).


Updates `@aws-cdk/toolkit-lib` from 1.19.3 to 1.21.0
- [Release notes](https://github.com/aws/aws-cdk-cli/releases)
- [Commits](https://github.com/aws/aws-cdk-cli/commits/@aws-cdk/toolkit-lib@v1.21.0/packages/@aws-cdk/toolkit-lib)

---
updated-dependencies:
- dependency-name: "@aws-cdk/toolkit-lib"
  dependency-version: 1.21.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: aws-cdk
...

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Author: dependabot[bot]