Update notes for submitted changes

* Upgrade error_prone_core to 2.3.1

75/75cab5321bb43d13eb889850f959de2aacd7ae

+Verified+1: CI Bot
+Code-Review+2: Matthias Sohn <matthias.sohn@sap.com>
+Submitted-by: Matthias Sohn <matthias.sohn@sap.com>
+Submitted-at: Mon, 23 Apr 2018 19:18:34 -0400
+Reviewed-on: https://git.eclipse.org/r/121400
+Project: jgit/jgit
+Branch: refs/heads/master