added accelerate version specification in open webui quickstart(#11948)

docs/mddocs/Quickstart/open_webui_with_ollama_quickstart.md

@@ -75,6 +75,7 @@ You may run below commands to install Open WebUI dependencies:
   # Install Dependencies
   cd ./backend
   pip install -r requirements.txt -U
+  pip install --pre --upgrade accelerate
   ```
 
 - For **Windows users**:
@@ -90,6 +91,7 @@ You may run below commands to install Open WebUI dependencies:
   :: Install Dependencies
   cd .\backend
   pip install -r requirements.txt -U
+  pip install --pre --upgrade accelerate
   ```
 
 ### 3. Start the Open-WebUI