Update CHANGELOG for v2.1.1

Avoid `println` which outputs to stderr. (argoproj#844)

Argo 2.0 outputted logs to stdout. This reinstates that behaviour.

Issue argoproj#810 - `argo install`does not install argo ui (argoproj…

…#811)

Update change log for 2.1.0-beta1 release

Fix make release target

Support setting UI base Url (argoproj#722)

* Support setting baseUrl in Argo UI

* Issue argoproj#716 - Add ui-base-url installer argument

Fix argo-ui download links to point to v2.0.0-beta1

Fix artifactory unit test and linting issues

Add 'release' make target. Improve CLI help and set version from git …

…tag. Uninstaller for UI

Support submission of manifests via URL