release note: Add pending release notes for already merged code

Follow on to ceph#31774

Signed-off-by: David Zafman <dzafman@redhat.com>
(cherry picked from commit 65d03ba)

PendingReleaseNotes

@@ -45,3 +45,13 @@
   value determined by the config options, for the average for any of the 3 intervals.
   New admin command ``ceph daemon osd.# dump_osd_network [threshold]`` will
   do the same but only including heartbeats initiated by the specified OSD.
+
+* The configuration value ``osd_calc_pg_upmaps_max_stddev`` used for upmap
+  balancing has been removed. Instead use the mgr balancer config
+  ``upmap_max_deviation`` which now is an integer number of PGs of deviation
+  from the target PGs per OSD.  This can be set with a command like
+  ``ceph config set mgr mgr/balancer/upmap_max_deviation 2``.  The default
+  ``upmap_max_deviation`` is 1.  There are situations where crush rules
+  would not allow a pool to ever have completely balanced PGs.  For example, if
+  crush requires 1 replica on each of 3 racks, but there are fewer OSDs in 1 of
+  the racks.  In those cases, the configuration value can be increased.