cross-platform backup tool First beta v2.1.2b1 release towards v2.2.0

Hello everybody,

This is a beta release so that many people can test before this becomes 
the next stable release. All changes are documented in the changelog 
<https://github.com/rdiff-backup/rdiff-backup/blob/v2.1.2b1/CHANGELOG.adoc#new-in-v2-1-2b1>. 
Check especially the changes (marked with /CHG/) which might impact your 
workflow. Since the last alpha:

   * support for Python 3.6 has been dropped,
   * return codes have changed and are now more detailed, see man-page
     for details,
   * more stability around failed file handling,
   * a lot of code changes under the hood (which you shouldn't notice but
     just that you don't think we were lazy),
   * and we even found some time for new features (only using the new
     API), like better locking of repositories and being able to regress
     the last backup even if it was successful, possibly one of the
     longest standing RFEs.

Please use this release to test and report issues 
<https://github.com/rdiff-backup/rdiff-backup/issues/new?assignees=&labels=&template=bug_report.md&title=%5BBUG%5D>, 
especially regarding:

   * usage in client/server in combination with version v2.0.5 of
     rdiff-backup
   * usage under Windows (and MacOS/X)
   * usage of the new API with |--api-version 201|

It's a beta version, it should be feature-stable but still have some 
bugs. Here is what remains to be done before 2.2.0 can be released 
<https://github.com/rdiff-backup/rdiff-backup/issues?q=is%3Aopen+is%3Aissue+milestone%3A2.2.0>, 
planned to be done before end of the year.

The installation procedure hasn't changed much and is available from the 
readme 
<https://github.com/rdiff-backup/rdiff-backup/blob/v2.1.2b1/README.adoc> 
(beta packages might or might not be offered by the maintainers, in 
doubt install via |pip install rdiff-backup==2.1.2b1| under Linux and 
use the attached binaries under Windows). You might want to use the 
side-by-side installation 
<https://github.com/rdiff-backup/rdiff-backup/blob/v2.1.2b1/docs/migration.adoc#side-by-side-installation> 
to safeguard your productive installation.

—

This release has 19 assets:

   * rdiff-backup-2.1.2b1.tar.gz
   * rdiff-backup-2.1.2b1.win32exe.zip
   * rdiff-backup-2.1.2b1.win64exe.zip
   * 
rdiff_backup-2.1.2b1-cp310-cp310-manylinux_2_12_i686.manylinux2010_i686.whl
   * 
rdiff_backup-2.1.2b1-cp310-cp310-manylinux_2_12_x86_64.manylinux2010_x86_64.whl
   * 
rdiff_backup-2.1.2b1-cp310-cp310-manylinux_2_17_x86_64.manylinux2014_x86_64.whl
   * rdiff_backup-2.1.2b1-cp310-cp310-win32.whl
   * rdiff_backup-2.1.2b1-cp310-cp310-win_amd64.whl
   * 
rdiff_backup-2.1.2b1-cp37-cp37m-manylinux_2_12_i686.manylinux2010_i686.whl
   * 
rdiff_backup-2.1.2b1-cp37-cp37m-manylinux_2_12_x86_64.manylinux2010_x86_64.whl
   * 
rdiff_backup-2.1.2b1-cp37-cp37m-manylinux_2_17_x86_64.manylinux2014_x86_64.whl
   * 
rdiff_backup-2.1.2b1-cp38-cp38-manylinux_2_12_i686.manylinux2010_i686.whl
   * 
rdiff_backup-2.1.2b1-cp38-cp38-manylinux_2_12_x86_64.manylinux2010_x86_64.whl
   * 
rdiff_backup-2.1.2b1-cp38-cp38-manylinux_2_17_x86_64.manylinux2014_x86_64.whl
   * 
rdiff_backup-2.1.2b1-cp39-cp39-manylinux_2_12_i686.manylinux2010_i686.whl
   * 
rdiff_backup-2.1.2b1-cp39-cp39-manylinux_2_12_x86_64.manylinux2010_x86_64.whl
   * 
rdiff_backup-2.1.2b1-cp39-cp39-manylinux_2_17_x86_64.manylinux2014_x86_64.whl
   * Source code (zip)
   * Source code (tar.gz)

Visit the release page 
<https://github.com/rdiff-backup/rdiff-backup/releases/tag/v2.1.2b1> to 
download them.

Kind Regards, Eric