BF(TST): allow for a annex repo version to upgrade if running in adjusted branches

[yarikoptic]

Closes #6925

or we could completely dissolve this test, although I think it might have some nominal value

[codecov]

Codecov Report

Merging #6927 (1636a30) into maint (06f50e0) will increase coverage by 1.06%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##            maint    #6927      +/-   ##
==========================================
+ Coverage   90.03%   91.09%   +1.06%     
==========================================
  Files         354      354              
  Lines       46246    46250       +4     
  Branches     6595     6597       +2     
==========================================
+ Hits        41637    42131     +494     
+ Misses       4593     4103     -490     
  Partials       16       16              

Impacted Files	Coverage Δ
datalad/support/tests/test_annexrepo.py	97.97% <100.00%> (+<0.01%)	⬆️
datalad/_version.py	45.68% <0.00%> (-0.28%)	⬇️
datalad/support/annexrepo.py	90.52% <0.00%> (+0.08%)	⬆️
datalad/core/distributed/tests/test_push.py	98.94% <0.00%> (+0.21%)	⬆️
datalad/distribution/tests/test_create_sibling.py	79.65% <0.00%> (+0.21%)	⬆️
datalad/log.py	88.44% <0.00%> (+0.39%)	⬆️
datalad/local/addurls.py	94.95% <0.00%> (+0.45%)	⬆️
datalad/utils.py	88.08% <0.00%> (+0.52%)	⬆️
datalad/core/local/create.py	99.29% <0.00%> (+0.70%)	⬆️
datalad/tests/utils_testrepos.py	94.11% <0.00%> (+0.84%)	⬆️
... and 10 more

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

[yarikoptic]

ok, all EU DataLad'ers are vacationing and I need to keep CI greenish to stay sane. So I will proceed with the merge of this test fixup.