require numpy 1.x for testing, until quantities/neo support numpy 2.0

.github/workflows/full-test.yml

@@ -32,6 +32,7 @@ jobs:
       run: |
         python -m pip install --upgrade pip
         python -m pip install pytest pytest-cov coveralls flake8
+        python -m pip install "numpy<2"
     - name: Install Brian 2
       run: |
         python -m pip install brian2