CI: rename julia-runtest branch

[codecov[bot]]

Codecov Report

Patch coverage has no change and project coverage change: +3.72 :tada:

Comparison is base (51b1838) 93.08% compared to head (43e32ec) 96.81%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #263 +/- ## ========================================== + Coverage 93.08% 96.81% +3.72% ========================================== Files 6 6 Lines 767 785 +18 ========================================== + Hits 714 760 +46 + Misses 53 25 -28 ``` [see 4 files with indirect coverage changes](https://codecov.io/gh/JuliaMath/FixedPointNumbers.jl/pull/263/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=JuliaMath) Help us with your feedback. Take ten seconds to tell us [how you rate us](https://about.codecov.io/nps?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=JuliaMath). Have a feature suggestion? [Share it here.](https://app.codecov.io/gh/feedback/?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=JuliaMath)

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[timholy]

The Arm failures are unfortunate but this is at least an improvement.