chore: Changelog for 1.1.1 (#3425)

Signed-off-by: Mattia Lavacca <[email protected]>

Author: mlavacca

CHANGELOG/1.1-CHANGELOG.md

@@ -2,10 +2,34 @@
 
 ## Table of Contents
 
+- [v1.1.1](#v111)
 - [v1.1.0](#v110)
 - [v1.1.0-rc2](#v110-rc2)
 - [v1.1.0-rc1](#v110-rc1)
 
+# v1.1.1
+This is a patch release that fixes some issues with GRPCRoute v1alpha2 and session
+persistence, and backports some improvements on CI and the conformance suite. Details
+follow.
+
+## Changes by Kind
+
+### Bug Fixes
+
+- Make GRPCRoute v1alpha2's status a subresource, and restore the previous additional
+  printer columns (#3412, @kflynn)
+- Allow the header based session persistence not to have AbsoluteTimeout, by relaxing
+  CEL validation (#3215, @sanposhiho)
+
+### CI improvements
+
+- Perform CEL validation tests for multiple Kubernetes versions (#3417, @mlavacca,
+  @robscott)
+
+### Conformance suite improvements
+
+- Expose the gRPC client interface as a conformance suite option (#3095, @snehachhabria)
+
 # v1.1.0
 On behalf of Kubernetes SIG Network, we are pleased to announce the v1.1 release!
 This release includes the graduation of several features to GA, including both