add make install

Author: SimonBlanke

.github/workflows/test.yml

@@ -106,6 +106,7 @@ jobs:
         run: |
           python -m pip install --upgrade pip
           python -m pip install build pytest
+          make install
           python -m pip install scikit-learn==${{ matrix.sklearn-version }}
 
       - name: Run sklearn integration tests for ${{ matrix.sklearn-version }}