Update maven.yml

Add Python setup.

.github/workflows/maven.yml

@@ -40,6 +40,11 @@ jobs:
           ${{ runner.os }}-pip-
     - name: Fail on whitespace errors
       run: git show HEAD --check
+    - name: Set up Python
+      uses: actions/setup-python@v5
+      with:
+        python-version: '3.10'
+        cache: 'pip' # caching pip dependencies
     - name: Install global requirements
       run: pip3.10 install -r requirements.txt
     - name: Run Spotless