Create .changes files for reproducible builds

[JanZerebecki]

release rpm files currently do not have .changes files, but these are needed to extract SOURCE_DATE_EPOCH for reproducible builds.

Using the time stamp of the last commit to the input, which is the 000package-groups source package, as the time for the changes entry would be reproducible, however there is resistance to that.

The other date that would is somewhat related is the time of the last source change for any input to the whole distribution, however AFAIK this date is not cheap enough to compute for OBS-VCS. This hopefully changes once we move to git. But I think the change date of 000package-groups makes more sense conceptually, because AFAIK that is the only information that can causes a change.

However to not delay making progress with reproducible builds in Factory, I propose this change which is non-reproducible, by using the current wall-clock time. We can revisit this later.

See https://reproducible-builds.org/ for more general information on this topic.

This is an alternative for: #3062

[DimStar77]

The other date that would is somewhat related is the time of the last source change for any input to the whole distribution, however AFAIK this date is not cheap enough to compute for OBS-VCS. This hopefully changes once we move to git. But I think the change date of 000package-groups makes more sense conceptually, because AFAIK that is the only information that can causes a change.

• The 000package-releases contains the TW snapshot version - i.e is changed daily
• The weakremover.inc is updated by a bot and dynamically changes whenever a package is removed - without changes in 000package-groups
  i.e the date of 000package-groups is in no way the only relevant change to the -releases package

[Vogtinator]

But I think the change date of 000package-groups makes more sense conceptually, because AFAIK that is the only information that can causes a change.

No, as the generated content depends on all other packages in the repo, e.g. version number and weakremovers.

[Vogtinator]

This is missing the "only if the output changes" part which is important otherwise it would commit changes on every run

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 0% with 14 lines in your changes are missing coverage. Please review.

Project coverage is 28.24%. Comparing base (9919e02) to head (63a8d50).
Report is 28 commits behind head on master.

Files	Patch %	Lines
pkglistgen/tool.py	0.00%	14 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3064      +/-   ##
==========================================
- Coverage   28.31%   28.24%   -0.08%     
==========================================
  Files          86       86              
  Lines       14799    14840      +41     
==========================================
  Hits         4191     4191              
- Misses      10608    10649      +41     

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[JanZerebecki]

Now it should only change the changes files if there is something else to commit.

Note: after this is merged, the %changelog in the spec.in files in 000package-groups probably needs to be removed before the following run.

[Vogtinator]

LGTM. Let's try this next week