6.9.0

Features:

• Add --all-extras flag to pip-compile (#1630). Thanks @apljungquist
• Support Exclude Package with custom unsafe packages (#1509). Thanks @hmc-cs-mdrissi

Bug Fixes:

• Fix compile cached vcs packages (#1649). Thanks @atugushev
• Include py.typed in wheel file (#1648). Thanks @FlorentJeannot

Other Changes:

• Add pyproject.toml & modern packaging to introduction. (#1668). Thanks @hynek