Pin numpy upper version on CI

.github/workflows/test.yml

@@ -139,7 +139,7 @@ jobs:
       - name: Install dependencies
         shell: bash -l {0}
         run: |
-          mamba install --yes -q "python~=${PYTHON_VERSION}=*_cpython" mkl numpy scipy pip mkl-service graphviz cython pytest coverage pytest-cov pytest-benchmark pytest-mock sympy
+          mamba install --yes -q "python~=${PYTHON_VERSION}=*_cpython" mkl "numpy<1.26" scipy pip mkl-service graphviz cython pytest coverage pytest-cov pytest-benchmark pytest-mock sympy
           # numba-scipy downgrades the installed scipy to 1.7.3 in Python 3.9, but
           # not numpy, even though scipy 1.7 requires numpy<1.23. When installing
           # PyTensor next, pip installs a lower version of numpy via the PyPI.