fix: typo in workflow for solver

Author: xNok

.github/workflows/solve_problem.yml

@@ -28,7 +28,7 @@ jobs:
           python -m pip install --upgrade pip
           if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
           if [ -f test-requirements.txt ]; then pip install -r test-requirements.txt; fi
-          python -m pip install ./models+or-tools
+          python -m pip install ./models_or-tools
 
       - name: Run the script
         run: python ./models_or-tools/problems/${{ github.event.inputs.problem }}.py