What happened: Running syft without any arguments used to return help text and exit 1, but now the help text isn't shown.

What you expected to happen: Help text to be printed when running Syft without args.

How to reproduce it (as minimally and precisely as possible): Run syft on the command line.

Anything else we need to know?:

Environment:

• Output of syft version:

Application:   syft
Version:       0.19.0
BuildDate:     2021-06-30T01:31:58Z
GitCommit:     2de56c074917b159fdd76fc6b1da974b4c53ca2e
GitTreeState:  clean
Platform:      darwin/amd64
GoVersion:     go1.16.5
Compiler:      gc

• OS (e.g: cat /etc/os-release or similar): macOS 11.4