Release rpkg-1.57

[Ondrej Nosek]

Hi all,

a new version rpkg-1.57 is released.

This is mostly a bugfix update with improvements for building modules and
flatpaks

- Set configuration in case of "clone --branches" as well
- Send source mtime to dist-git
- Specify package manager for mock-config
- Add contributing guide
- Validate the module build optional argument when parsing the argument
- Add config options to parse the base module (e.g. platform) stream from
the dist-git branch and apply a buildrequire override
- Add the ability to pass in buildrequire and require overrides on a module
build
- Raise an error if the module build command receives optional arguments
that conflict
- Add flatpak-build subcommand

More specific changelog (web documentation):
https://docs.pagure.org/rpkg/releases/1.57.html

Updates:
https://bodhi.fedoraproject.org/updates/?builds=rpkg-1.57-2.el6&build...

Alternative link:
https://bodhi.fedoraproject.org/updates/?packages=rpkg&page=1

rpkg is available from PyPI.

Regards
Ondrej Nosek