* 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.

Resolves: #1401

* Use os.execvp for poetry run

* Use subprocess.Popen for Windows

* Handle env kwargs

* Fix specification of Python versions for dependencies using double
  pipe (`||`) instead of using an array which leads to confusion (see for
  instance https://github.com/sdispater/poetry/issues/847).

* Fixes #847

Signed-off-by: mr.Shu <mr@shu.io>

Resolves: #1080

Closes: #1303

* Update issue templates, thanks @explosion for the inspiration.

Direct support questions to StackOverflow instead.

* Remove stale issue templates.

* Update ---bug-report.md

* Update ---documentation.md

* Update about.py

* Update add.py

* Update update.py

Some packages (like `pygame-music-grid`) have unparseable metadata.
This resulted in a ValueError. pip ignores packages like these, so it's reasonable
to do the same in poetry itself and only display the well-formed ones.

Fixes #1345.
Fixes #637.

This reverts commit be03ab9e.