Prep for 3.1.2 of CPS

- updated release notes
- bumbed cps version to 3.1.2-SNAPSHOT from 3.1.1-SNAPSHOT

Issue-ID: CPS-1304
Change-Id: Ie65f76032b087dffc716e00fa3868f89f165a6b1
Signed-off-by: mpriyank <priyank.maheshwari@est.tech>
19 files changed