feat: write help message to stdout

[theurichde]

Fixes #1359

Description of the change

Writes output of --help / -h to Stdout instead of Stderr

Benefits

Follows GNU standards for CLIs where --help --version are supposed to be printed to Stdout

Possible drawbacks

Applicable issues

• fixes kubeseal --help writes to stderr instead of stdout #1359

Additional information

[agarcia-oss]

Thanks for the change! it seems to be working as expected

 $ ./kubeseal --help | grep version
  --version                          Print version information and exit