[CI] Fix ref for scheduled pipelines

[christophfroehlich]

• workflow schedules are (only) run from master branch
• without giving an explicit ref argument the humble+iron workflows have checked out the master branch, which obviously fails
• fixed now with this if-clause in the ref field

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (5b5f332) 47.53% compared to head (9a6e526) 47.53%.
Report is 3 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1361   +/-   ##
=======================================
  Coverage   47.53%   47.53%           
=======================================
  Files          41       41           
  Lines        3549     3549           
  Branches     1931     1931           
=======================================
  Hits         1687     1687           
+ Misses        459      458    -1     
- Partials     1403     1404    +1     

Flag	Coverage Δ
unittests	47.53% <ø> (ø)

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see 1 file with indirect coverage changes

[fmauch]

Looks good to me. Is there a reason why the tests are failing on debian and RHEL? Seems unrelated to this PR, though.

[christophfroehlich]

Looks good to me. Is there a reason why the tests are failing on debian and RHEL? Seems unrelated to this PR, though.

flaky tests, yeah: #1338 (comment)