Use Dict for type instead of dict (#262)

This change is to fix a bug as dict is not compatible with Python 3.8

Feature: SHIV_PREPEND_PYTHONPATH (#254)

* Add SHIV_PREPEND_PYTHONPATH and environment type-safety

* Bump version 1.0.7

Fix a typo in tox.ini, release 1.0.6 (#252)

Release 1.0.5

Remove Py3.6 and Py3.7 from tox/actions (#238)

Fix python-version-specific paths in PYTHONPATH

When SHIV_EXTED_PYTHONPATH is used, PYTHONPATH env variable gets not only
zipapp sit-packages and other new stuff, but also the default sys.path
of the current Python (for ex. Python3.10). This breaks ability to run
a different version of Python in a subprocess, because PYTHONPATH takes
precedence over default sys.path, and so a subprocess starting Python3.9
will attempt to use Python 3.10 builtin modules, and will most likely break
in unpredictable ways. This change fixes that by only adding new paths
which appear after injecting zipapp site-packages.

Release 1.0.2

Release 1.0.1

1.0 release

Release 0.5.1