Install wkhtmltopdf before tests

.github/workflows/ci.yml

@@ -14,7 +14,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Setup Python
         uses: actions/setup-python@v4
@@ -24,6 +24,8 @@ jobs:
       - name: Install Python dependencies
         run: |
           cd test_app
+          wget https://github.com/wkhtmltopdf/packaging/releases/download/0.12.6.1-2/wkhtmltox_0.12.6.1-2.jammy_amd64.deb
+          sudo apt install -y ./wkhtmltox_0.12.6-1.bionic_amd64.deb
           pip install --upgrade pip
           pip install -r requirements.txt