Suggestion: nocolor fallbacks for echo-style / enable color for github actions

[balupton]

Since implementing 3b85eb1 which disables TTY on "dumb" terminals, the colors on GitHub Actions have been disabled, which makes reading the logs very difficult. GitHub Actions actually does support rendering colors, despite being a dumb terminal.

The solution here is either to revamp echo-style with plenty of nocolor fallbacks (a good thing to do in general), or to have is-color-enabled check for GitHub Actions and enable colors (a quick fix).