ci(github workflows): 移除linux/arm/v7平台构建支持

删除了build_docker.yml中的arm/v7平台配置，缩减支持的构建架构

Author: xiaozhou26

.github/workflows/build_docker.yml

@@ -49,7 +49,7 @@ jobs:
         with:
           context: .
           file: Dockerfile
-          platforms: linux/amd64,linux/arm64,linux/arm/v7
+          platforms: linux/amd64,linux/arm64
           push: true
           tags: |
             ${{ env.GHCR_REPO }}:latest