Update foamlib requirement from <0.7,>=0.3 to >=0.3,<0.8 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@v0.3.0...v0.7.2)

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

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

tests/requirements.txt

@@ -2,4 +2,4 @@ pytest>=7,<9
 pytest-asyncio-cooperative>=0.37.0,<0.38
 numpy>=1,<3
 scipy==1.*
-foamlib>=0.3,<0.7
+foamlib>=0.3,<0.8