Add release note

Author: MoteHue

releasenotes/notes/cephadm-pre-post-commands-now-have-defaults-b42ce9b13fa6d63b.yaml

@@ -0,0 +1,8 @@
+---
+features:
+  - |
+    The Cephadm pre and post commands now support default commands with the
+    variables ``cephadm_commands_pre_default`` and
+    ``cephadm_commands_post_default``. As such, any extra commands should be
+    added to the variables ``cephadm_commands_pre_extra`` and
+    ``cephadm_commands_post_extra``.