poetry 1.1.0 on Python PyPI

The init command will now use existing pyproject.toml if possible (#2448).
Error messages when metadata information retrieval fails have been improved (#2997).

Fixed parsing of version constraint for rc prereleases (#2978).
Fixed how some metadata information are extracted from setup.cfg files (#2957).
Fixed return codes returned by the executor (#2981).
Fixed whitespaces not being accepted for the list of extras when adding packages (#2985).
Fixed repositories specified in the pyproject.toml file not being taken into account for authentication when downloading packages (#2990).
Fixed permission errors when installing the root project if the site-packages directory is not writeable (#3002).
Fixed environment marker propagation when exporting to the requirements.txt format (#3002).
Fixed errors when paths in run command contained spaces (#3015).