Add versioning promise (#1630)

To indicate the importance of reading the release notes.

README.md

@@ -247,6 +247,12 @@ For more information about contributing please read the [contribution guidelines
 
 If you want to have a chat with us, feel free to join our channel on [kubernetes Slack workspace](https://kubernetes.slack.com/archives/C05SW4GKPL3) (get invite [here](https://communityinviter.com/apps/kubernetes/community)).
 
+## Versioning
+
+Current project releasing follows [ZerOver](https://0ver.org), with the following versioning promise:
+- In new releases, API might break and functionality might change significantly. Any such releases increment the second digit in the release tag. The users **really need to read the release notes** before upgrading to these releases.
+- For all other releases, the third digit increments. Upgrades to these versions can be done blindly without any risk to running environments. Reading the release notes is recommended nevertheless.
+
 ## Security
 
 While we strive to create secure software, there is always a chance that we