Use numpy<2 in CI

It's probably pthelma that should be specifying numpy<2, because its
wheels only support that, but we'll likely wait until gdal improves on
that so that we can actually use numpy>=2.

.github/workflows/run-tests.yml

@@ -47,7 +47,7 @@ jobs:
         sudo -u postgres psql -U postgres -c "create database openmeteo owner runner"
         python -m pip install --upgrade pip 'setuptools<58'  # See https://stackoverflow.com/questions/69123406
         CPLUS_INCLUDE_PATH=/usr/include/gdal C_INCLUDE_PATH=/usr/include/gdal pip install 'gdal==3.4.1'
-        pip install 'psycopg2>=2.9,<3' codecov coverage isort flake8 'black<25'
+        pip install 'psycopg2>=2.9,<3' codecov coverage isort flake8 'black<25' 'numpy<2'
         pip install -r requirements.txt
         pip install -r requirements-dev.txt
         npm install