Update step_by_step.rst

删除多余的3.2章节

docs/step_by_step.rst

@@ -159,14 +159,6 @@
     $ cd /opt
     $ git clone https://github.com/jumpserver/coco.git && cd coco && git checkout master
 
-**3.2 安装依赖**
-
-::
-
-    $ cd /opt/coco/requirements
-    $ yum -y install $(cat rpm_requirements.txt)
-    $ pip install requirements.txt
-
 
 **3.2 安装依赖**
 
@@ -295,4 +287,4 @@ Luna 已改为纯前端，需要 Nginx 来运行访问
 
 6.3 运行 Nginx
 
-6.4 访问 http://192.168.244.144
\ No newline at end of file
+6.4 访问 http://192.168.244.144