Update CHANGELOG.md

Merge pull request getredash#1559 from getredash/new_upgrade

New and shiny upgrade script

Update release date of 0.12.0.

Fix build configuration

Update version

Bump version.

Merge pull request getredash#1167 from ariarijp/fix-bootstrap-script-…

…for-ubuntu

Fix the version of setuptools on bootstrap script for Ubuntu

Update CirlceCI config to build hotfix branch

Bump version.

Merge pull request getredash#1017 from getredash/fix/ds_cli

Add data source to default group when creating with CLI