Add legend colors 3454

[clarenced]

Summary
As mentionned in #3454, this PR explains the color legend when using the upgrade-interactive command.

Test plan

cd-charles@CDCHARLESW764 MINGW64 ~/Documents/workspace/angular2-test (master)
$ yarn upgrade-interactive
yarn upgrade-interactive v0.26.0-0
info Color legend :
 "<red>"    : Patch Update Backward-compatible bug fixes
 "<yellow>" : Minor Update backward-compatibles features
? Choose which packages to update. (Press <space> to select, <a> to toggle all, <i> to inverse selection)

[bestander]

Thanks, @clarenced!