Update ibridges requirement from ~=1.2 to ~=1.3 in /tests/unit

Updates the requirements on [ibridges](https://github.com/iBridges-for-iRODS/iBridges) to permit the latest version.
- [Release notes](https://github.com/iBridges-for-iRODS/iBridges/releases)
- [Commits](iBridges-for-iRODS/iBridges@v1.2.0...v1.3.0)

---
updated-dependencies:
- dependency-name: ibridges
  dependency-type: direct:production
...

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

tests/unit/requirements.txt

@@ -1 +1 @@
-ibridges~=1.2
+ibridges~=1.3