Version 5.10.0

Changes:

• refs: Image names are now checked using Docker's rules. Malformed names are refused with a clear message.
• install: Added support for images pinned by digest, e.g. ubuntu@sha256:.... The download is verified against the digest. A pinned image can be reinstalled from the cache without network.
• build, push: A digest is refused in build -t and push.
• install: Fixed intact image layers sometimes refused with "does not match its digest".
• http: Redirects can no longer move a download from HTTPS to plain HTTP. --allow-insecure lifts this.
• registry: --allow-insecure no longer applies to Docker Hub. It is always verified.
• http: Network requests give up after 2 minutes of silence instead of hanging forever.
• http: Invalid URLs and registry addresses now show an error message instead of a traceback.
• build, login: Bytes that are not valid UTF-8 in arguments, build args or image environment no longer cause a traceback.
• list, remove: --image no longer prints control characters from cache entries as they are.
• sync, copy: Files that change during the transfer are handled correctly. No more missed updates or wrong permissions.
• sysdata: Fake /proc/stat now lists the same CPUs as /proc/cpuinfo. Existing containers are fixed automatically.
• tests, docs: Tests now pass with the default open files limit. Comments and docs were brought up to date.