Reconsider app binary name

[yermulnik]

Could this please be considered to rename the app binary to not overlap with a common *NIX tool whoami (man 1 whoami) so that those who prefer to not use Docker but install binary directly with go install (or by other means, e.g. Homebrew) don't suffer from a need to apply local quirks for this app to not overlap with whoami from base *NIX distros. Thank you in advance.