Document major release policy

README.md

@@ -64,3 +64,22 @@ violations:
 ```
 bundle exec rubocop --regenerate-todo
 ```
+
+## New major releases
+
+As described above, we will do new minor releases of voxpupuli-rubocop with
+newer RuboCop dependencies. We also ship a rubocop.yml that people can use. This
+file currently configures Ruby 2.7 as a target version. This will be adjusted in
+major releases.
+
+User of voxpupuli-rubocop don't have to use our rubocop.yml, they can just rely
+on our curated list of rubocop dependencies. Or overwrite the target version in
+their own rubocop.yaml:
+
+```
+inherit_gem:
+  voxpupuli-rubocop: rubocop.yml
+
+AllCops:
+  TargetRubyVersion: '3.3'
+```