Run test activities using Python 3.11

The recent release of h5py 3.8.0 includes wheels for Python 3.11.

.gitlab-ci.yml

@@ -52,9 +52,7 @@ nox-310:
       - "*.whl"
 
 # Run all of the test activities using Python 3.11.
-# NOTE: this is currently blocked by the absence of h5py wheels.
-# See https://github.com/h5py/h5py/issues/2146 for details.
-# nox-311:
-#   image: python:3.11-slim
-#   script:
-#     - nox
+nox-311:
+  image: python:3.11-slim
+  script:
+    - nox