Update changelog

Signed-off-by: mulhern <amulhern@redhat.com>

Author: mulkieran

CHANGES.txt

@@ -1,3 +1,23 @@
+stratis-cli 3.6.0 (UNRELEASED)
+==============================
+Required stratisd version: 3.6.0
+
+Recommended development environment: Fedora 38
+Lowest supported Python interpreter: 3.9
+
+- Update for r6 D-Bus revision:
+  https://github.com/stratis-storage/stratis-cli/pull/981
+
+- Adapt to r6 StopPool interface:
+  https://github.com/stratis-storage/stratis-cli/pull/982
+
+- Add man page field for blockdev UUID:
+  https://github.com/stratis-storage/stratis-cli/pull/978
+
+- Tidies and Maintenance:
+  https://github.com/stratis-storage/stratis-cli/pull/980
+
+
 stratis-cli 3.5.1
 =================
 Required stratisd version: 3.5.0