With this patch, it is possible to pass username and password directly
on the command line with:
```shell
yarr --auth 'username:password'
```
The corresponding environment variable comes handy with containers:
```shell
YARR_AUTH='username:password' yarr
```
Before this patch, an `authfile` with multiple column symbols was not
valid.
After this patch, all characters after the first `:` constitute the
password, until EOL.