fix: build failure caused by not correctly retrieving the version during the build.

[H-Sofie]

当我在执行

pip install alibabacloud_credentials -U

时，会提示构建失败的错误消息：

Collecting alibabacloud-credentials
  Using cached https://pypi.tuna.tsinghua.edu.cn/packages/b7/0c/1b0c5f4c2170165719b336616ac0a88f1666fd8690fda41e2e8ae3139fd9/alibabacloud-credentials-1.0.2.tar.gz (30 kB)
  Preparing metadata (setup.py) ... error
  error: subprocess-exited-with-error

  × python setup.py egg_info did not run successfully.
  │ exit code: 1
  ╰─> [7 lines of output]
      Traceback (most recent call last):
        File "<string>", line 2, in <module>
        File "<pip-setuptools-caller>", line 35, in <module>
        File "D:\xxx\System\Temp\pip-install-fjnrk_89\alibabacloud-credentials_8d1bc2f0b418402a9128f01e8f12ef51\setup.py", line 34, in <module>
          VERSION = __import__(PACKAGE).__version__
                    ^^^^^^^^^^^^^^^^^^^
      ModuleNotFoundError: No module named 'alibabacloud_credentials'
      [end of output]

  note: This error originates from a subprocess, and is likely not a problem with pip.
error: metadata-generation-failed

× Encountered error while generating package metadata.
╰─> See above for output.

note: This is an issue with the package mentioned above, not pip.
hint: See above for details.

我想可能是因为它在生成元数据阶段就去 import 自己的模块拿版本号，但当前环境里还没有这个模块，于是构建错误。
此 PR 调整构建脚本，直接读取源文件中的 __version__ 字面值，防止缺少依赖问题。

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