Fix the python version and cache pip

.github/workflows/test.yml

@@ -5,17 +5,15 @@ on: [push]
 jobs:
   build:
     runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        python-version: ["3.11"]
     steps:
     - uses: actions/checkout@v4
       with:
         fetch-depth: 0
-    - name: Set up Python ${{ matrix.python-version }}
+    - name: Set up Python
       uses: actions/setup-python@v5
       with:
-        python-version: ${{ matrix.python-version }}
+        python-version: 3.11
+        cache: pip
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip