Pex

This is a fix release which addresses issues related to build time
work_dir creation, virtualenv, and sh_boot support.

In the unlikely event of a UUID collision in atomic workdir creation,
pex could overwrite an existing directory and cause a corrupt state.
When building a shell bootable `--sh-boot` pex the `--runtime-pex-root`
was not always respected based on the condition of the build
environment, and the value of the PEX_ROOT.

* Fail on atomic_directory work_dir collision. (1905)
* Use raw_pex_root when constructing sh_boot pexes. (1906)
* Add support for offline downloads (1898)

This release brings a long-awaited upgrade of the Pip Pex uses, but
behind a `--pip-version 22.2.2` flag you must opt in to. Pex will then
use that version of Pip if it can (your Pex operations target Python

This release fixes things such that pex lockfiles can be created and
updated using the Pex PEX when local projects are involved.

* Fix `pex3 lock ...` when run from the Pex PEX. (1874)

This is a hotfix release that fixes a further corner missed by 1863 in
the Pex 2.1.101 release whereby Pex would fail to install
platform-specific packages on Red Hat based OSes.

In addition, an old but only newly discovered bug in
`--inherit-path={prefer,fallback}` handling is fixed. Previously only
using `PEX_INHERIT_PATH={prefer,fallback}` at runtime worked properly.

In the process of fixing the old `--inherit-path={prefer,fallback}` bug,
also fix another old bug handling modern virtualenv venvs under Python
2.7 during zipapp execution mode PEX boots.

* Fix wheel installs: account for purelib & platlib. (1867)
* Fix `--inhert-path` handling. (1871)
* Error using pex + `virtualenv>=20.0.0` + python 2.7 (992)

This release fixes a corner-case revealed by python-certifi-win32 1.6.1
that was not previously handled when installing certain distributions.

* Make wheel install `site-packages` detection robust. (1863)

This release fixes a hole in the lock creation `--target-system` feature
added in 1823 in Pex 2.1.95.

* Fix lock creation `--target-system` handling. (1858)