Can't add VCS package as depedency

[ridv]

• I have searched the issue tracker and believe that this is not a duplicate.

Make sure you run commands with -v flag before pasting the output.

Steps to reproduce

Attempt to add VCS dependency on version v2.18.2:

pdm add "venmo-api-unoffical @ git+https://github.com/evanpurkhiser/venmo-api-unofficial.git@main" 

Actual behavior

Dependency fails to be added with an error about the Version being None:

[RequirementError]: Invalid version for venmo-api-unoffical @ git+https://github.com/evanpurkhiser/venmo-api-unofficial.git@main: Invalid version:
'None'

This change in behavior seems to have been introduced by 00de69c .

Expected behavior

According to the docs this should result in the package being added as a dependency.

Environment Information

# Paste the output of `pdm info && pdm info --env` below:
PDM version:
  2.18.2
Python Interpreter:
  /home/ridv/git/venmo-auto-cashout/.venv/bin/python (3.12)
Project Root:
  /home/ridv/git/venmo-auto-cashout
Local Packages:

{
  "implementation_name": "cpython",
  "implementation_version": "3.12.3",
  "os_name": "posix",
  "platform_machine": "x86_64",
  "platform_release": "5.15.153.1-microsoft-standard-WSL2",
  "platform_system": "Linux",
  "platform_version": "#1 SMP Fri Mar 29 23:14:13 UTC 2024",
  "python_full_version": "3.12.3",
  "platform_python_implementation": "CPython",
  "python_version": "3.12",
  "sys_platform": "linux"
}

[ridv]

Thank you so much for looking at this! Appreciate it!