• Upgrade Go version to 1.13.7, alpine to 3.11 and other dependencies.
• Support Manifest List v2. This enables the proper display of multi-arch images,
  such as those generated by Docker BuildX or manually (thanks to Christoph Honal @StarGate01).
  So now we support the following formats: Manifest v2 schema 1, Manifest v2 schema 2, Manifest List v2 schema 2
  and all their confusing combinations.
• Amend representation of the tag info page.
• Change logging library, add "-log-level" argument and put most of the logging into DEBUG mode.
• You can define timezone when running container by adding TZ env var, e.g. "-e TZ=America/Los_Angeles"
  (thanks to @gminog).
• Fix initial ownership of /opt/data dir in Dockerfile.
• Hide repositories with 0 tags count.
• Compatibility fix with docker_auth v1.5.0.