AWS IoT Over-the-air Update Library v3.4.0

LTS Version Change (#453)

* Updating versions for LTS 2.0, added relevant PRs to the CHANGELOG

* Fixed submodule issue, removed extra line from CHANGELOG.md

* Added a coverity README.md

* Fixing an incorrect link, adding a newline to end of README

Co-authored-by: Soren Ptak <skptak@amazon.com>