Fixes #4575

Related to:

- https://github.com/pypa/packaging/issues/456
- https://github.com/python-poetry/poetry-export-plugin/issues/12

brew installs these automatically

This reverts commit 6e53b90d.

Closes #4479

The previous implementation would fail to install packages on Windows
because it creates a `Path` starting with a slash. Such a `Path` is
invalid on Windows. Instead, use `Link` and `url_to_path`.

* Improves wording of exception when calculated hash absent from lockfile and
extracts archive hashing and validation to a separate method

I think this could be further improved by representing the hashes as
a dataclass containing the hash type and the string digest. The types of
hashes would be more robust then instead of hardcoding sha256 here and
in `FileDependency.hash()`. It would also enable enumeration of
hash types of known hashes so that `FileDependency.hash()` could return
a list of hashes based on requested types.

Doing this might alleviate the md5/sha256 problems arising from changes
in poetry-core 1.0.6+ that affect Poetry 1.1.7+ users using Artifactory.

Co-authored-by: Arun Babu Neelicattu <arun.neelicattu@gmail.com>

This is a continuation of/supersedes #1742.

Co-authored-by: Egor <Birdi7@users.noreply.github.com>
Co-authored-by: Bjorn Neergaard <bjorn@neersighted.com>

Minor whitespace cleanup, push the $PATH out of the Matrix (which is
more aligned with Github Actions), and make the list of tasks more
obvious.

* installer: improve error handling and logging

Co-authored-by: Bjorn Neergaard <bjorn@neersighted.com>

* installer: default to using in-built venv module

This change refactors virtual environment creation and introduces a new
wrapper to handle command execution etc. If venv module is not
available, in cases like that of the ubuntu distribution where the
module is not part of the default python install, the virtualenv
package is used by fetching the appropriate zipapp for the package for
the python runtime.

Resolves: #4089
Resolves: #4093

* ci/installer: upload failure logs

* installer: preserve existing environment on failure

This change ensures that if creation of a new environment fails, any
previously existing environment is restored.

Co-authored-by: Bjorn Neergaard <bjorn@neersighted.com>

Remove the old sonnet script, as well as the obsolete
make-nix-release.sh and Makefile.

The last one is maybe more borderline, but it's ill-maintained and has
no consumers as best I can tell.

Co-authored-by: Bjorn Neergaard <bjorn@neersighted.com>

`whitelist_externals` is now deprecated in Tox >= 3.18 and has been renamed to `allowlist_externals`

https://tox.readthedocs.io/en/latest/config.html#conf-allowlist_externals

This change speeds up poetry command start time by 50ms compared to
current master and around 250ms compared to 1.1.5.

Relates-to: #3502

When installing Poetry through `install-poetry.py`, if `pip` is not
available, Exception should not be raised, rather installation should
be aborted with user-friendly error msg.

Fixes #4521

Co-authored-by: TurtleNishant <nishant@turtlelectric.com>
Co-authored-by: Bjorn Neergaard <bjorn@neersighted.com>

This change removes `__future__` imports and 'coding: utf-8' 
declarations.

Co-authored-by: Jason Racine <jason.racine@uplight.com>

This change adds dependabot configuration with updates disabled to
allow for restriction of manifest file selection used by the
dependency graph.

Ref: https://docs.github.com/en/code-security/supply-chain-security/keeping-your-dependencies-updated-automatically/configuration-options-for-dependency-updates

Ref: https://www.python.org/dev/peps/pep-0314/#keywords-optional 

Resovles: #4183

Related-to: #4142

HTTPretty handling of thread exception is incomplete, causing issues
for test runs. This change works around the issue by ignoring the
relevant warnings.

Pytest issues a warning as it attempts to collect `TestApplication`.
This change renames the class to `PoetryTestApplication`.

Upstream issue with pip 21.1.1 was resolved in 21.1.2. This version of
pip was embedded in virtualenv versions 20.4.7 and above.

Relates-to: python-poetry#4042

This change ensures that when complete packages are created dependency
inherits subdirectory from package if supported.

This change ensures that when complete packages are created dependency
inherits source and resolved refs from package.

This change ensures that the tests support upcoming (>1.1.0a6) changes
dropping default branch assumptions for vcs dependencies.