Release containers-image-proxy 0.11.1 (is_retryable) #268

Unblocks composefs/composefs-rs#407, which needs Error::is_retryable() from bootc-dev/containers-image-proxy-rs#155 (merged in 1e3e1b4, unreleased; latest release 0.11.0). Upstream releases are a version-bump PR followed by a maintainer-pushed v* tag, which runs cratesio-release.yml. The bot prepares the bump PR only; tagging and publishing are for the maintainers.

Generated-by: https://github.com/cgwalters/#llms