chore: Update build script to include mock command

This commit updates the build script in the .gitlab-ci.yml file to include a mock command. The previous build.sh command was removed and replaced with an echo command to print a message indicating that AnduinOS cannot be built in Docker. This change improves the clarity of the build process and ensures that developers are aware of the limitation.

Author: Anduin2017

.gitlab-ci.yml

@@ -4,5 +4,4 @@ stages:
 build:
   stage: build
   script:
-    - cd ./src
-    - ./build.sh -
+    - echo "Mock script. This is because AnduinOS can't be built in Docker."

README.md

@@ -1,5 +1,8 @@
 # AnduinOS
 
+[![GPL licensed](https://img.shields.io/badge/license-GPL-blue.svg)](https://gitlab.aiursoft.cn/anduin/anduinos/-/blob/master/LICENSE)
+[![Discussions](https://img.shields.io/badge/discussions-join-blue)](https://github.com/Anduin2017/AnduinOS/discussions)
+[![Website](https://img.shields.io/website?url=https%3A%2F%2Fwww.anduinos.com%2F)](https://www.anduinos.com/)
 [![ManHours](https://manhours.aiursoft.cn/r/gitlab.aiursoft.cn/anduin/anduinos.svg)](https://gitlab.aiursoft.cn/anduin/anduinos/-/commits/master?ref_type=heads)
 
 <img align="right" width="100" height="100" src="./src/mods/30-gnome-extension-arcmenu-patch/logo.svg">