0.4

CHANGES:

• Use GNU tar format instead of UStar for copy operations (@TheLortex #82, reviewed @dra27).
  This enables copying from sources containing long file names (>100 characters).

• Add support for secrets (@TheLortex #63, reviewed by @talex5).
  The obuilder spec's run command supports a new secrets fields, which allows to temporarily
  mount secret files in an user-specified location. The sandbox build context has an additional
  secrets parameter to provide values for the requested keys.

• Limit permissions on temporary directories (@talex5 #67)

• Check Linux kernel version support for btrfs (@kit-ty-kate #68)

• Generalise obuilder sandbox, removing runc/linux specifc pieces and
  making the S.SANDBOX interface more general
  (@patricoferris #58, reviewed by @talex5, @avsm, @MisterDA)

• Convert --fast-sync back to a flag (@talex5 #72)

• Support Fmt.cli and Logs.cli flags. (@MisterDA #74, reviewed by @talex5)
  For Fmt the new options are --color=always|never|auto
  For Log the new options are:
  -v, --verbose Increase verbosity
  --verbosity=LEVEL (absent=warning)
  Be more or less verbose. LEVEL must be one of quiet, error,
  warning, info or debug. Takes over -v.

• Minor cleanup changes (@talex5 #76)

• Fix deprecations in Fmt 0.8.10 (@tmcgilchrist #80)

• Remove travis-ci and replace with Github Actions (@MisterDA #84)

• Add RSync store backend for obuilder to support macOS builders (@patricoferris #88, reviewed @talex5)

• Fixes for ZFS tests in CI (@patricoferris #91)