Document semver policy

Author: markelog

readme.md

@@ -18,3 +18,7 @@ Configure ESLint with a `.eslintrc` file using the following contents:
 ## Proposing changes
 
 Over time, ESLint implements new rules, alter existing ones, and retire old ones. Changes to the jQuery config should be made as pull requests to this repo, with issues raised on jQuery contibute [repository](https://github.com/jquery/contribute.jquery.org/issues).
+
+## Semver policy
+
+Same approach as in ESLint, see https://github.com/eslint/eslint#user-content-semantic-versioning-policy.