'vipaccess show' example should have example output too

[jidanni]

README.md says:

Generating access codes using an existing credential
The vipaccess [show] option will also do this for you: by default it generates codes based on the credential in ~/.vipaccess, but you can specify an alternative credential file or specify the OATH "token secret" on the command line.

usage: vipaccess show [-h] [-s SECRET | -f DOTFILE]

optional arguments:
  -h, --help            show this help message and exit
  -s SECRET, --secret SECRET
                        Specify the token secret on the command line (base32
                        encoded)
  -f DOTFILE, --dotfile DOTFILE
                        File in which the credential is stored (default
                        ~/.vipaccess

OK, but it ought to go a tiny bit farther, and show an actual run of vipaccess show, with output.