feat: add support for exit code in terraspace fmt command

[duckst3r]

This is a 🙋‍♂️ feature or enhancement.

• I've added tests (if it's a bug, feature or enhancement) --> N/A
• I've adjusted the documentation (if it's a feature or enhancement) --> N/A
• The test suite passes (run bundle exec rspec to verify this)

Summary

This change add support for exit 1 return code while running terraspace fmt command with errors.

Note : I am not a ruby developer, feel free to give me insights to improve the code.

How to Test

Just test the exit code while running terraspace fmt for the following scenarii :

1. The configuration has no error, terraform fmt SHOULD return exit code 0.
2. The configuration has one or more error, terraform fmt SHOULD run until the end and SHOULD return a exit code 1.

[tongueroo]

Released in terraspace v2.2.7 Thanks!