Exit with non-zero RC on failure

**Is your feature request related to a problem? Please describe.**
When runnning `satis build`, and updating a package fails with 'Failed to update ...', Satis does not exit with a non-zero RC. This can cause errors to be missed.

**Describe the solution you'd like**
Exit with non-zero RC on failure.

**Describe alternatives you've considered**
N/A

**Additional context**
N/A