Celebrate the success of composition more, so it's no overshadowed by previous WARN

[prasek]

Description

Steps to reproduce

1. Clone https://github.com/apollographql/supergraph-demo
2. Run make demo-managed:w

Expected result

We should celebrate the SUCCESS of composition in green text, to offset the red WARN that first-time users see when publishing a federated graphs.

Actual result

The success of composition is understated.

Environment

Rover Info:
Version: 0.1.6
Install Location: /Users/prasek/.cargo/bin/rover
OS: Mac OS 11.4.0 [64-bit]
Shell: /bin/zsh