Add docs for inline exclude newer (#6831)

See https://github.com/astral-sh/uv/pull/6562

docs/guides/scripts.md

@@ -201,6 +201,29 @@ print(Point)
 is not installed — see the documentation on [Python versions](../concepts/python-versions.md) for
 more details.
 
+## Improving reproducibility
+
+uv supports an `exclude-newer` field in the `tool.uv` section of inline script metadata to limit uv
+to only considering distributions released before a specific date. This is useful for improving the
+reproducibility of your script when run at a later point in time.
+
+The date must be specified as an [RFC 3339](https://www.rfc-editor.org/rfc/rfc3339.html) timestamp
+(e.g., `2006-12-02T02:07:43Z`).
+
+```python title="example.py"
+# /// script
+# dependencies = [
+#   "requests",
+# ]
+# [tool.uv]
+# exclude-newer = "2023-10-16T00:00:00Z"
+# ///
+
+import requests
+
+print(requests.__version__)
+```
+
 ## Using different Python versions
 
 uv allows arbitrary Python versions to be requested on each script invocation, for example: