title: poetry: how to install from git subdirectory?
body: <p>I want to install <code>feast</code> python package with <code>poetry</code>.</p>
  <p><code>pip3 install git+https://github.com/feast-dev/feast#subdirectory=sdk/python</code> works okay,</p>
  <p>but <code>poetry add git+https://github.com/feast-dev/feast#subdirectory=sdk/python</code>gives an error:</p>
  <pre><code>  CalledProcessError
  
    Command '['git', '--git-dir', '/tmp/pypoetry-git-feas51ct2_me/.git', '--work-tree', '/tmp/pypoetry-git-feas51ct2_me', 'checkout', 'subdirectory=sdk/python']' returned non-zero exit status 1.
  
    at /usr/lib/python3.8/subprocess.py:516 in run
         512│             # We don't call process.wait() as .__exit__ does that for us.
         513│             raise
         514│         retcode = process.poll()
         515│         if check and retcode:
      →  516│             raise CalledProcessError(retcode, process.args,
         517│                                      output=stdout, stderr=stderr)
         518│     return CompletedProcess(process.args, retcode, stdout, stderr)
         519│ 
         520│ 
  </code></pre>
  <p>How can I fix it?</p>