chore: Remove deprecated package_api_docs rule (dart-lang/pubspec_parse#141)

* chore: Remove deprecated package_api_docs rule

* chore: Add changelog entry

pkgs/pubspec_parse/CHANGELOG.md

diff --git a/pkgs/pubspec_parse/CHANGELOG.md b/pkgs/pubspec_parse/CHANGELOG.md
index aa99cbb..91613cc 100644
--- a/pkgs/pubspec_parse/CHANGELOG.md
+++ b/pkgs/pubspec_parse/CHANGELOG.md
@@ -1,6 +1,7 @@
 ## 1.3.1-wip
 
 - Require Dart 3.2
+- Remove deprecated package_api_docs rule
 
 ## 1.3.0