Allow URL requirements in editable installs (#1614)

## Summary

If an editable package declares a direct URL requirement, we currently
error since it's not considered an "allowed" requirement. We need to add
those URLs to the allow-list.

Closes https://github.com/astral-sh/uv/issues/1603.

scripts/editable-installs/hatchling_editable/hatchling_editable/__init__.py

@@ -0,0 +1,2 @@
+def func():
+    pass

scripts/editable-installs/hatchling_editable/pyproject.toml

@@ -0,0 +1,22 @@
+[build-system]
+requires = ["hatchling"]
+build-backend = "hatchling.build"
+
+[project]
+name = "hatchling-editable"
+description = 'A simple editable package with a URL dependency.'
+readme = "README.md"
+requires-python = ">=3.7"
+license = "MIT"
+keywords = []
+authors = [
+  { name = "Astral Software Inc.", email = "hey@astral.sh" },
+]
+classifiers = []
+dependencies = [
+  "iniconfig @ https://files.pythonhosted.org/packages/ef/a6/62565a6e1cf69e10f5727360368e451d4b7f58beeac6173dc9db836a5b46/iniconfig-2.0.0-py3-none-any.whl"
+]
+version = "0.1.0"
+
+[tool.hatch.metadata]
+allow-direct-references = true

scripts/editable-installs/poetry_editable/pyproject.toml

@@ -2,7 +2,7 @@
 name = "poetry-editable"
 version = "0.1.0"
 description = ""
-authors = ["konstin <konstin@mailbox.org>"]
+authors = ["Astral Software Inc. <hey@astral.sh>"]
 
 [tool.poetry.dependencies]
 python = "^3.10"