fix: egg segment for local dependency

[micaelmalta]

Pull Request Check List

• A news fragment is added in news/ describing what is new.
• Test cases added for changed code.

Describe what you have changed in this PR.

The command pdm add -e ./demo --dev result on a line added to pyproject.toml

dev = [
    "-e file:///${PROJECT_ROOT}/demo#egg=demo",
]

Any following pdm add will result on an error

Adding packages to dev dev-dependencies: -e file:///${PROJECT_ROOT}/demo#egg=demo
[RequirementError]: Editable requirement is only supported for VCS link or local directory.

[codecov-commenter]

Codecov Report

Base: 85.37% // Head: 85.33% // Decreases project coverage by -0.03% ⚠️

Coverage data is based on head (8a361c9) compared to base (40d2c01).
Patch coverage: 100.00% of modified lines in pull request are covered.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1552      +/-   ##
==========================================
- Coverage   85.37%   85.33%   -0.04%     
==========================================
  Files          91       91              
  Lines        8053     8059       +6     
  Branches     1909     1910       +1     
==========================================
+ Hits         6875     6877       +2     
- Misses        789      792       +3     
- Partials      389      390       +1     

Flag	Coverage Δ
unittests	85.15% <100.00%> (-0.04%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
src/pdm/models/requirements.py	93.67% <100.00%> (ø)
src/pdm/utils.py	86.63% <100.00%> (+0.35%)	⬆️
src/pdm/models/repositories.py	79.92% <0.00%> (-0.79%)	⬇️
src/pdm/termui.py	89.85% <0.00%> (-0.73%)	⬇️
src/pdm/cli/actions.py	78.50% <0.00%> (-0.25%)	⬇️

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

☔ View full report at Codecov.
📢 Do you have feedback about the report comment? Let us know in this issue.

[frostming]

Thanks 🎉