docs(readme): warn against managing projects with filter

README.md

@@ -362,6 +362,13 @@ or `--workspace` then only the options you provide will be searched.
 A string which will be passed to `new RegExp()` to match against package names
 that should be included.
 
+> ⚠️ `filter` was originally intended as a convenience to be used from the
+> command line to filter the output of `syncpack list`, **it is not recommended
+> to add this to your config file to manage your project more generally**.
+>
+> Instead use [`versionGroups`](#versiongroups) and/or
+> [`semverGroups`](#semvergroups).
+
 ### `indent`
 
 The character(s) to be used to indent your package.json files when writing to