!290 Update supported operating system in install . Related issue...

!290 Update supported operating system in install . Related issue https://gitee.com/mindspore/docs/issues/I1LVKZ
Merge pull request !290 from ZhidanLiu/master

install/mindspore_cpu_install.md

@@ -97,7 +97,7 @@
 
 | 版本号                 | 操作系统            | 可执行文件安装依赖                                           | 源码编译安装依赖         |
 | ---------------------- | :------------------ | :----------------------------------------------------------- | :----------------------- |
-| MindArmour master | Ubuntu 16.04（及以上） x86_64 | - [Python](https://www.python.org/downloads/) 3.7.5 <br> - MindSpore master<br> - 其他依赖项参见[setup.py](https://gitee.com/mindspore/mindarmour/blob/master/setup.py) | 与可执行文件安装依赖相同 |
+| MindArmour master | Ubuntu 18.04 x86_64 | - [Python](https://www.python.org/downloads/) 3.7.5 <br> - MindSpore master<br> - 其他依赖项参见[setup.py](https://gitee.com/mindspore/mindarmour/blob/master/setup.py) | 与可执行文件安装依赖相同 |
 
 - 在联网状态下，安装whl包时会自动下载`setup.py`中的依赖项，其余情况需自行安装。
 

install/mindspore_cpu_install_en.md

@@ -97,7 +97,7 @@ If you need to conduct AI model security research or enhance the security of the
 
 | Version | Operating System | Executable File Installation Dependencies | Source Code Compilation and Installation Dependencies |
 | ---- | :--- | :--- | :--- |
-| MindArmour master | Ubuntu 16.04 or later x86_64 | - [Python](https://www.python.org/downloads/) 3.7.5 <br> - MindSpore master <br> - For details about other dependency items, see [setup.py](https://gitee.com/mindspore/mindarmour/blob/master/setup.py). | Same as the executable file installation dependencies. |
+| MindArmour master | Ubuntu 18.04 x86_64 | - [Python](https://www.python.org/downloads/) 3.7.5 <br> - MindSpore master <br> - For details about other dependency items, see [setup.py](https://gitee.com/mindspore/mindarmour/blob/master/setup.py). | Same as the executable file installation dependencies. |
 
 - When the network is connected, dependency items in the `setup.py` file are automatically downloaded during .whl package installation. In other cases, you need to manually install dependency items.
 

install/mindspore_gpu_install.md

@@ -189,7 +189,7 @@
 
 | 版本号                 | 操作系统            | 可执行文件安装依赖                                           | 源码编译安装依赖         |
 | ---------------------- | :------------------ | :----------------------------------------------------------- | :----------------------- |
-| MindArmour master | Ubuntu 16.04（及以上） x86_64 | - [Python](https://www.python.org/downloads/) 3.7.5 <br> - MindSpore master <br> - 其他依赖项参见[setup.py](https://gitee.com/mindspore/mindarmour/blob/master/setup.py) | 与可执行文件安装依赖相同 |
+| MindArmour master | Ubuntu 18.04 x86_64 | - [Python](https://www.python.org/downloads/) 3.7.5 <br> - MindSpore master <br> - 其他依赖项参见[setup.py](https://gitee.com/mindspore/mindarmour/blob/master/setup.py) | 与可执行文件安装依赖相同 |
 
 - 在联网状态下，安装whl包时会自动下载`setup.py`中的依赖项，其余情况需自行安装。
 

install/mindspore_gpu_install_en.md

@@ -191,7 +191,7 @@ If you need to conduct AI model security research or enhance the security of the
 
 | Version | Operating System | Executable File Installation Dependencies | Source Code Compilation and Installation Dependencies |
 | ---- | :--- | :--- | :--- |
-| MindArmour master | Ubuntu 16.04 or later x86_64 | - [Python](https://www.python.org/downloads/) 3.7.5 <br> - MindSpore master <br> - For details about other dependency items, see [setup.py](https://gitee.com/mindspore/mindarmour/blob/master/setup.py). | Same as the executable file installation dependencies. |
+| MindArmour master | Ubuntu 18.04 x86_64 | - [Python](https://www.python.org/downloads/) 3.7.5 <br> - MindSpore master <br> - For details about other dependency items, see [setup.py](https://gitee.com/mindspore/mindarmour/blob/master/setup.py). | Same as the executable file installation dependencies. |
 
 - When the network is connected, dependency items in the `setup.py` file are automatically downloaded during .whl package installation. In other cases, you need to manually install dependency items.