Bump ibek from 1.5.3 to 1.5.5

Bumps [ibek](https://github.com/epics-containers/ibek) from 1.5.3 to 1.5.5.
- [Release notes](https://github.com/epics-containers/ibek/releases)
- [Changelog](https://github.com/epics-containers/ibek/blob/main/CHANGELOG.rst)
- [Commits](epics-containers/ibek@1.5.3...1.5.5)

---
updated-dependencies:
- dependency-name: ibek
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

requirements.txt

@@ -1,3 +1,3 @@
-ibek==1.5.3
+ibek==1.5.5
 # to install direct from github during development in the dev branch:
 #git+https://github.com/epics-containers/ibek.git@dev