[Doc] double quote cmake package in build.inc.md (vllm-project#12840)

Signed-off-by: Louis Ulmer <[email protected]>

Author: jitseklomp

docs/source/getting_started/installation/cpu/build.inc.md

@@ -10,7 +10,7 @@ Second, install Python packages for vLLM CPU backend building:
 
 ```console
 pip install --upgrade pip
-pip install cmake>=3.26 wheel packaging ninja "setuptools-scm>=8" numpy
+pip install "cmake>=3.26" wheel packaging ninja "setuptools-scm>=8" numpy
 pip install -v -r requirements-cpu.txt --extra-index-url https://download.pytorch.org/whl/cpu
 ```