Support datree upgrade command

[noaabarki]

Describe the solution you'd like

Add new upgrade command to install the latest datree version.

• The command should support only macOS & Linux.
• The command should check if the user installed Datree with brew and if so, the command should fail and return a message “Looks like you installed Datree via brew, to upgrade datree run - brew upgrade datree”
• The command should not support pinned or user-defined versions.

Requirements Golang mid-level.

Reference: https://github.com/cli/cli/blob/trunk/pkg/cmd/extension/command.go

[amustaque97]

Hi there, I would love to give it a shot, can you please assign this issue to me?