x11-fm/doublecmd: update to 1.2.8 gamma release (+)

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What's new: https://github.com/doublecmd/doublecmd/wiki/Changes-in-version-1.2.0
Release motes: https://github.com/doublecmd/doublecmd/releases/tag/v1.2.8
Full changelog: https://github.com/doublecmd/doublecmd/compare/v1.1.32...v1.2.8