Add missing indexes upgrade notes to 3.[0|1] release notes

The upgrade to `3.0` results in a `changes` index version upgrade to
`v56`. The upgrade to `3.1` results in the following index upgrades:
* `accounts` to `v11`
* `changes` to `v57`
* `groups` to `v8`

Change-Id: Ibcde6f51033ec6dbfb52c2bf02797ad8fe45b29f
2 files changed