[Documentation] Add changelog entry for version 3.11.1.

Signed-off-by: Giacomo Marciani <[email protected]>

Author: gmarciani

CHANGELOG.md

@@ -1,6 +1,16 @@
 CHANGELOG
 =========
 
+3.11.1
+------
+
+**CHANGES**
+- Pyxis is now disabled by default and it must be manually enabled on the head node.
+
+**BUG FIXES**
+- Fix an issue in the way we configure the Pyxis Slurm plugin in ParallelCluster that can lead to job submission failures.
+- Add missing permissions required by login nodes to the public template of policies.
+
 3.11.0
 ------