Changelog:
===========
-Added a default to an internal API that is used by scikit-build-core.
-$HFPR_VERSION is now replaced by the package version in the PyPI readme.
The version is not available in CLI mode, therefore it's replaced by the dummy
value of 42.0.
Signed-off-by: Wang Mingyu <wangmy@fujitsu.com> Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>