docs: update changelog for config_settings attribute

CHANGELOG.md

@@ -85,7 +85,14 @@ END_UNRELEASED_TEMPLATE
 * (bootstrap) {obj}`--bootstrap_impl=system_python` now supports the
   {obj}`main_module` attribute.
 * (bootstrap) {obj}`--bootstrap_impl=system_python` now supports the
-  {any}`RULES_PYTHON_ADDITIONAL_INTERPRETER_ARGS` attribute.
+  {any}`RULES_PYTHON_ADDITIONAL_INTERPRETER_ARGS` environment variable.
+* (rules) The `py_binary`, `py_test`, and `py_wheel` rules now have a
+  {obj}`config_settings` attribute to control build flags within the build graph.
+  Custom settings can be added using {obj}`config.add_transition_setting` in
+  `MODULE.bazel` files, or {obj}`py_repositories(transition_settings=...)` in
+  `WORKSPACE` files. See the
+  {ref}`common-deps-with-multiple-pypi-versions` guide on using common
+  dependencies with multiple PyPI versions` for an example.
 
 
 {#v1-6-0}

docs/howto/common-deps-with-multipe-pypi-versions.md → docs/howto/common-deps-with-multiple-pypi-versions.md

@@ -1,3 +1,4 @@
+(common-deps-with-multiple-pypi-versions)=
 # How to use a common set of dependencies with multiple PyPI versions
 
 In this guide, we show how to handle a situation common to monorepos