docs: Update README.md to fix pip install llama cpp server (#1187)

Without the single quotes, when running the command, an error is printed saying no matching packages found on pypi. Adding the quotes fixes it

```bash
$ pip install llama-cpp-python[server]
zsh: no matches found: llama-cpp-python[server]
```

Co-authored-by: Andrei <abetlen@gmail.com>

README.md

@@ -505,14 +505,14 @@ This allows you to use llama.cpp compatible models with any OpenAI compatible cl
 To install the server package and get started:
 
 ```bash
-pip install llama-cpp-python[server]
+pip install 'llama-cpp-python[server]'
 python3 -m llama_cpp.server --model models/7B/llama-model.gguf
 ```
 
 Similar to Hardware Acceleration section above, you can also install with GPU (cuBLAS) support like this:
 
 ```bash
-CMAKE_ARGS="-DLLAMA_CUBLAS=on" FORCE_CMAKE=1 pip install llama-cpp-python[server]
+CMAKE_ARGS="-DLLAMA_CUBLAS=on" FORCE_CMAKE=1 pip install 'llama-cpp-python[server]'
 python3 -m llama_cpp.server --model models/7B/llama-model.gguf --n_gpu_layers 35
 ```