Deprecation warning fix in test_iohelper.py

Fix to a Deprecation Warning caused by \[, which is not a recognized escape sequence in a non-raw string. The Warning is displayed in the warnings summary when compiling the lhcb stack, after it fails to compile due to another issue being fixed in !4962 (merged). (thanks to @sargueda for spotting it)

=============================== warnings summary ===============================
tests/pytest/test_iohelper.py:30
  /swdev/sargueda/stack_pytest_migration/LHCb/GaudiConf/tests/pytest/test_iohelper.py:30: DeprecationWarning: invalid escape sequence \[
    r"\[.*/([^/]*.*)\]", r"[\1]", "^\[Gaudi"

marked this merge request as ready

changed the description

Hi @anmorris, could we have a CI-test without downstream in this little MR

added bug fix label

added ci-test-triggered label

added RTA label

• [2025-03-10 11:54] Validation started with lhcb-master-mr#12817

added 11 commits

• 5ef057f0...7923c673 - 10 commits from branch master
• 9cfcba35 - Merge remote-tracking branch 'origin/master' into pytest-migration

Compare with previous version

assigned to @pkopciew

Hi @jonrob, feel free to proceed with this MR

resolved all threads

merged

mentioned in commit a99d41cb