Update foamlib requirement in /tests

Updates the requirements on [foamlib](https://github.com/gerlero/foamlib) to permit the latest version.
- [Release notes](https://github.com/gerlero/foamlib/releases)
- [Commits](gerlero/foamlib@v0.1.0...v0.6.0)

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

Signed-off-by: dependabot[bot] <[email protected]>

tests/requirements.txt

@@ -1,3 +1,3 @@
 pytest>=7,<7.3
 pytest-asyncio-cooperative>=0.37.0,<0.38
-foamlib>=0.1.0,<0.6.0
+foamlib>=0.1.0,<0.7.0