Use the unit test cache again.

Author: AhmedBasem20

.github/workflows/unit_test.yml

@@ -23,6 +23,7 @@ jobs:
         uses: actions/setup-python@v5
         with:
           python-version: ${{ matrix.python-version }}
+          cache: 'pip'
       # You can test your matrix by printing the current Python version
       - name: Display Python version
         run: python -c "import sys; print(sys.version)"