ci: 更新 OSS 许可证比较文件的脚本

-将 PowerShell 脚本替换为 Bash 脚本
-优化了文件比较逻辑，提高了脚本的可读性和性能
- 此修改确保了在 GitHub Actions 中更一致地处理文件更改

Author: ArcticFoxPro

.github/workflows/update-oss-licenses-dist.yml

@@ -36,12 +36,12 @@ jobs:
       - name: Compare files
         id: compare-files
         run: |
-          if (-not (git diff --exit-code origin/main)) {
-            Write-Output "files_changed=true" | Out-File -FilePath $env:GITHUB_ENV -Append
-          } else {
-            Write-Output "files_changed=false" | Out-File -FilePath $env:GITHUB_ENV -Append
-          }
-        shell: pwsh
+          if ! git diff --exit-code origin/main; then
+            echo "files_changed=true" >> $GITHUB_ENV
+          else
+            echo "files_changed=false" >> $GITHUB_ENV
+          fi
+        shell: bash
 
       - name: Create Pull Request
         if: env.files_changed == 'true'