This reverts commit 65ba952f.

* Add custom certificate authority and client certificate support

* Add documentation on certificates

* Add cli options to publish for cert and custom ca

* Fix requests+pathlib problem and logic hole when BasicAuth+certs are used

* Rename custom-ca to cert

* Make black happy

Fixes #1153

Currently Poetry will detect that it is running in a usual virtual env
created with "python -m venv" and will not create an additional env.

This commit extends this logic to Conda, which uses different
environment variables to indicate running in a virtual env.

Conda's "base" env is treated specially to avoid polluting global
namespace.

* Refactor the environment management code

* Improve executable selection when current Python is incompatible

* Allow uploading of wheels with local version identifier

Signed-off-by: Oleg Höfling <oleg.hoefling@gmail.com>

* extracted pep-427-style name/version escaping to helper functions

Signed-off-by: Oleg Höfling <oleg.hoefling@gmail.com>

-- `package` from provider.py:search_for_directory
   is missing root_dir value. This fixes the problem.
-- fix https://github.com/sdispater/poetry/issues/1455

* Fix PATH being altered after installation even though choose not to

* Remove unuse updated list variable

Co-authored-by: adisbladis <adisbladis@gmail.com>

* Check that a git dependency resolves to a revision

A git dependency should be resolved to a full git revision (SHA-1).
When dealing with a git dependency, this is the only way to lock
the dependency in-place (because revisions are immutable).

* Check that a pinned git dependency resolves to a revision

There are three mutually exclusive parameters that can be used to
pin a git dependency: `branch`, `tag`, and `rev`.  Since they all
can be moving targets, they should be resolved to a full git
revision (SHA-1) to ensure a proper in-place lock.

This change highlights bug #1331 and currently fails.

* Make sure a git reference resolves to a revision

Do not lock a git dependency to a named reference but to a full
git revision instead.  This ensures reproducibility and security
as git revisions are immutable.

Fixes: #1331

Using poetry from master/develop branches or any recent alpha/beta release,
you can't add the requests package with the security extra.
The requests package requires the idna twice
(as a main dependency and as an optional one) and this case wasn't handled
properly in Locker._dump_package function.
These changes make the _dump_package ensures that
all elements of the constraints list have the same type
in order to make them renderable as TOML.