fix: install multicorn2 for daily tests (#488)

.github/workflows/python-package-daily.yml

@@ -26,7 +26,7 @@ jobs:
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip setuptools
-        python -m pip install -e '.[testing]'
+        python -m pip install -e '.[testing]' 'multicorn @ git+https://github.com/pgsql-io/multicorn2.git@v2.5'
     - name: Test with pytest
       run: |
         pytest --cov-fail-under=100 --cov=src/shillelagh -vv tests/ --doctest-modules src/shillelagh --without-integration --without-slow-integration