Adjust tests for Git's init.defaultBranch

[kyleam]

This series adjust for Git's 2.28's init.defaultBranch configuration option:

• Update a few test that fail when init.defaultBranch is set to a value other than "master".

• Set init.defaultBranch to a value other than "master" in the GitHub CI runs to (1) guard against regressions and (2) silence the many init.defaultBranch warnings emitted when running the tests.

~This PR is marked as a draft because it sits on top of gh-571. Here's the effective diff: https://github.com/repronim/reproman/compare/migrate-to-github-ci...harcoded-master~

[codecov[bot]]

Codecov Report

Merging #572 (636172b) into master (a7c5055) will decrease coverage by 0.16%. The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #572      +/-   ##
==========================================
- Coverage   89.20%   89.03%   -0.17%     
==========================================
  Files         149      149              
  Lines       13035    13054      +19     
==========================================
- Hits        11628    11623       -5     
- Misses       1407     1431      +24     

Impacted Files	Coverage Δ
reproman/distributions/tests/test_vcs.py	100.00% <100.00%> (ø)
reproman/support/jobs/tests/test_orchestrators.py	94.60% <100.00%> (+0.12%)	:arrow_up:
reproman/distributions/tests/test_venv.py	86.32% <0.00%> (-9.41%)	:arrow_down:
reproman/tests/skip.py	93.33% <0.00%> (-4.45%)	:arrow_down:
...eproman/interface/tests/test_backend_parameters.py	95.65% <0.00%> (-4.35%)	:arrow_down:
reproman/distributions/venv.py	86.04% <0.00%> (-2.33%)	:arrow_down:
reproman/config.py	88.46% <0.00%> (-1.29%)	:arrow_down:
reproman/resource/ssh.py	88.09% <0.00%> (-0.80%)	:arrow_down:
reproman/tests/test_utils.py	93.51% <0.00%> (-0.47%)	:arrow_down:
reproman/utils.py	86.97% <0.00%> (-0.17%)	:arrow_down:

---

Continue to review full report at Codecov.

Legend - Click here to learn more Δ = absolute <relative> (impact), ø = not affected, ? = missing data Powered by Codecov. Last update a7c5055...636172b. Read the comment docs.

[yarikoptic]

THANK YOU! Looks LGTM