setup on Python 2.7 is starting to break

使用 traceback 和注明的 pdfminer==20140328 workaround 重现 Python 2.7 安装失败。检查项目的依赖项和 setup 配置，以确定如何选择 pdfminer。当在不手动安装依赖项的情况下，Python 2.7 上的安装不再失败，并且已验证受支持的行为时，即表示完成。

Latest versions of pdfminer are no longer compatible with Python 2.7, which results in the install of pattern failing as well because pdfminer expects Python 3.6 or higher, but does not check for this.

Traceback (most recent call last):

  File "<string>", line 1, in <module>
  File "/tmp/pip-install-6LDKdm/pdfminer/setup.py", line 71, in <module>
    'Topic :: Text Processing',
  File "pattern-test/.env/local/lib/python2.7/site-packages/setuptools/__init__.py", line 145, in setup
    return distutils.core.setup(**attrs)
  File "/usr/lib/python2.7/distutils/core.py", line 151, in setup
    dist.run_commands()
  File "/usr/lib/python2.7/distutils/dist.py", line 953, in run_commands
    self.run_command(cmd)
  File "/usr/lib/python2.7/distutils/dist.py", line 972, in run_command
    cmd_obj.run()
  File "/tmp/pip-install-6LDKdm/pdfminer/setup.py", line 11, in run
    from pdfminer.cmapdb import convert_cmap
  File "/tmp/pip-install-6LDKdm/pdfminer/pdfminer/cmapdb.py", line 22, in <module>
    from .psparser import PSStackParser
  File "/tmp/pip-install-6LDKdm/pdfminer/pdfminer/psparser.py", line 4, in <module>
    from .utils import choplist
  File "/tmp/pip-install-6LDKdm/pdfminer/pdfminer/utils.py", line 219, in <module>
    0x00f8, 0x00f9, 0x00fa, 0x00fb, 0x00fc, 0x00fd, 0x00fe, 0x00ff,
  File "/tmp/pip-install-6LDKdm/pdfminer/pdfminer/utils.py", line 187, in <genexpr>
    PDFDocEncoding = ''.join(chr(x) for x in (
ValueError: chr() arg not in range(256)

Can be solved by installing pdfminer==20140328 first.