chore: update workflow to latest python version

.github/workflows/preview_pr.yml

@@ -16,15 +16,15 @@ jobs:
 
     steps:
     - name: Checkout DHIS2 Docs Builder Repository
-      uses: actions/checkout@v2
+      uses: actions/checkout@v4
       with:
         repository: dhis2/dhis2-docs-builder
 
 
-    - name: Set up Python 3.8
-      uses: actions/setup-python@v2
+    - name: Set up Python 3.9
+      uses: actions/setup-python@v4
       with:
-        python-version: '3.8'
+        python-version: '3.9'
 
     - name: Install dependencies
       run: |