Revert "get-poetry.py fallback to standard executables (#1878) (#2426)"

This reverts commit f8128221.

recurse clone submodules

* get-poetry.py fallback to standard executables

* documentation update

* fix typo due to cleanup

* favor python3 over python2 when creating launcher

* launcher favors 3.5 and up, else the first valid one it finds.

* favor any py3 over py2, not just 3.5+

Co-authored-by: Jonathan Piché <jpiche@coveo.com>

Co-authored-by: Jonathan Piché <jonapich@users.noreply.github.com>
Co-authored-by: Jonathan Piché <jpiche@coveo.com>

Release 1.0.9

Fix legacy repositories packages being continuously updated

Fix wrong indentation in mixology

Added git ssh example to docs

Added a cli add git ssh dependency example to documentation for easy reference.

Release 1.0.8

Release 1.0.7

Release 1.0.6

* Fix resolution of path, url and VCS dependencies

* Fix editable installation of Poetry packages

doc: fix issue template links in CONTRIBUTING.md

Update shell completion docs for prezto

fix: Gracefully handle read-only sdists

For a package without dependencies in pypi's database, like p4python,
the sdist is required.  The problem is p4python was developed in
perforce where all files are read-only by default and deleting the temp
directory fails.

So we need to use the custom-built temp directory and specially handle
read-only files to be able to use p4python in poetry.

Fixes #520

Bump actions/cache from v1 to v2

Small improvements to docs for version command

Fixes https://github.com/python-poetry/poetry/issues/2048