Export editable subpackage to requirements.txt with relative path instead of full file url

[dayongxie]

Feature Description

When exporting requirements, it is desired that dependencies of subpackages within the project directory use relative paths, such as:
-e ./packages/pkg-core

Problem and Solution

Using the current latest version 2.20.1 in a monorepo-style project, when exporting requirements.txt, the dependencies of subprojects are full paths:
-e file:///D:/opensource/pdm-example-monorepo/packages/pkg-core#egg=pkg-core
This requirements.txt file cannot be used elsewhere, and it is hoped that it can be changed to use relative paths.

Additional Context

No response

Are you willing to contribute to the development of this feature?

• Yes, I am willing to contribute to the development of this feature.