use setup-python to speed up workflow

.github/workflows/build.yml

@@ -13,14 +13,18 @@ jobs:
       uses: actions/checkout@v4
       with:
         fetch-depth: 0 # otherwise, you will failed to push refs to dest repo
-    - name: install python3
+    - name: install  ubuntu dependencies
       run: |
         sudo apt -y update
-        sudo apt -y install python3 python3-pip
         sudo apt -y install gnuplot
+    - name: Set up python3
+      uses: actions/setup-python@v5
+      with:
+        python-version: '3.12'
+        cache: 'pip' # caching pip dependencies
     - name: install python3 dependencies
       run: |
-        python3 -m pip install -r requirements.txt
+        pip install -r requirements.txt
     - name: setup texlive
       uses: teatimeguest/setup-texlive-action@v3
       with: