pip prod(deps): update mpi4py requirement from <3.1.6 to <3.1.7

Updates the requirements on [mpi4py](https://github.com/mpi4py/mpi4py) to permit the latest version.
- [Release notes](https://github.com/mpi4py/mpi4py/releases)
- [Changelog](https://github.com/mpi4py/mpi4py/blob/master/CHANGES.rst)
- [Commits](mpi4py/mpi4py@1.0...3.1.6)

---
updated-dependencies:
- dependency-name: mpi4py
  dependency-type: direct:production
...

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

requirements-mpi.txt

@@ -1,2 +1,2 @@
-mpi4py<3.1.6
+mpi4py<3.1.7
 ipyparallel<8.9