Add missing bazel-contrib#3046 reference to 1.7.0 changelog

I've had to reference this a couple times now and keep forgetting that
it's not in the changelog haha. I figured I'd remedy that.

Author: dougthor42

CHANGELOG.md

@@ -216,6 +216,9 @@ END_UNRELEASED_TEMPLATE
   from the [20251014] release.
 * (deps) (bzlmod) Upgraded to `bazel-skylib` version
   [1.8.2](https://github.com/bazelbuild/bazel-skylib/releases/tag/1.8.2)
+* (gazelle) Gazelle will now delete targets that have invalid an invalid `srcs`
+  attribute (typically because the only `srcs` file was deleted).
+  [#3046](https://github.com/bazel-contrib/rules_python/pull/3046)
 
 [20251014]: https://github.com/astral-sh/python-build-standalone/releases/tag/20251014