docker compose up, pip install -r requirements failed, 可能是由scrapy依赖的cryptography版本问题导致

[teadrinker2015]

#0 8.342 Collecting cryptography<40,>=38.0.0 (from pyOpenSSL->Scrapy==1.5.0->-r requirements.txt (line 1))
#0 8.857   Downloading https://pypi.doubanio.com/packages/6a/f5/a729774d087e50fffd1438b3877a91e9281294f985bda0fd15bf99016c78/cryptography-39.0.1.tar.gz (603kB)
#0 9.189     Complete output from command python setup.py egg_info:
#0 9.189     Traceback (most recent call last):
#0 9.189       File "<string>", line 1, in <module>
#0 9.189       File "/tmp/pip-build-gvp9q56u/cryptography/setup.py", line 93
#0 9.189         print(f"    Python: {'.'.join(str(v) for v in sys.version_info[:3])}")
#0 9.189                                                                             ^
#0 9.189     SyntaxError: invalid syntax
#0 9.189
#0 9.189     ----------------------------------------
#0 9.259 Command "python setup.py egg_info" failed with error code 1 in /tmp/pip-build-gvp9q56u/cryptography/
#0 11.38 You are using pip version 8.1.1, however version 23.0.1 is available.
#0 11.38 You should consider upgrading via the 'pip install --upgrade pip' command.
------
failed to solve: executor failed running [/bin/sh -c pip install -i https://pypi.douban.com/simple/ -r requirements.txt]: exit code: 1

具体可能是因为dockerfile中的python是3.5（ubuntu16.04默认，无法升级至3.6），而依赖的cryptography版本过高，导致在python3.6版本引入的f-string那里出现了语法错误。

建议将dockerfile中的unbuntu:16.04改为ubuntu:18.04，并添加RUN python -m pip install --upgrade pip