Forwarded request #1152936 from mcalabkova

- Update to 2.12.4
* Officially drop the support for Python 3.7.
* Allow exporting current project as editable dependency with pdm export.
* Use ==major.minor.* as default requires python for application projects.
* We now use the package-type field in the tool.pdm table to differentiate
between library and application projects.
* pdm lock now supports --update-reuse option to keep the pinned versions
in the lockfile if possible.
* Introduce a new lock strategy inherit_metadata to inherit and merge
markers from parent requirements. This is enabled by default when
creating a new lockfile.
* Allow excluding packages from the lockfile via tool.pdm.resolution.excludes
setting, the dependencies will also be skipped.
* Rename --no-lock option to --frozen-lockfile.
* Add --no-markers to export command to exclude markers from the output.
* Change the warning category emitted by deprecated_warning() to PDMDeprecationWarning.
* Rename the preferred_pins argument of provider classes to locked_candidates,
and deprecate the old name.
* Use env PDM_NO_EDITABLE as the default value for --no-editable option.