Update Python version and remove lxml installation

Updated Python version to 3.11 and removed lxml installation step.

Author: loekd

.github/workflows/NuGetCD.yml

@@ -34,10 +34,8 @@ jobs:
     - name: Setup Python
       uses: actions/setup-python@v5
       with:
-        python-version: '3.x'
+        python-version: '3.11'
 
-    - name: Install lxml
-      run: pip install lxml
     # Echo context
     - name: Echo context
       shell: pwsh