Add release notes for v0.231.0

Author: gustavodiaz7722

docs/release_notes/0.231.0.md

@@ -0,0 +1,15 @@
+# Release v0.231.0
+
+## 🐛 Bug Fixes
+
+- Grant ec2:DescribeSecurityGroups to the IPv6 VPC CNI role (#8837)
+
+## 🧰 Maintenance
+
+- Update coredns (#8841)
+- Update nvidia-device-plugin to v0.20.0 (#8840)
+
+## Acknowledgments
+
+The eksctl maintainers would like to sincerely thank @gustavodiaz7722 and @michaelbeaumont.
+