Upgrade to Debian bookworm (fixes #157)

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[copybara-service[bot]]

https://dart-review.googlesource.com/c/dart-docker/+/327700 has been updated with the latest commits from this pull request.

[copybara-service[bot]]

https://dart-review.googlesource.com/c/dart-docker/+/327700 has been updated with the latest commits from this pull request.