📖 Fix command Usage (#1814)

This changes the cmd Usage text to accurately represents the
supported syntax:

Usage:
  ./scorecard (--repo=<repo> | --local=<folder> | --{npm,pypi,rubygems}=<package_name>)
	 [--checks=check1,...] [--show-details] [flags]
...
      --repo string        repository to check (valid inputs: "owner/repo", "github.com/owner/repo", "https://github.com/owner/repo")
...

Signed-off-by: Arnaud J Le Hors <lehors@us.ibm.com>

cmd/root.go

@@ -37,8 +37,7 @@ import (
 
 const (
 	scorecardLong = "A program that shows security scorecard for an open source software."
-	scorecardUse  = `./scorecard [--repo=<repo_url>] [--local=folder] [--checks=check1,...]
-	 [--show-details] or ./scorecard --{npm,pypi,rubygems}=<package_name> 
+	scorecardUse  = `./scorecard (--repo=<repo> | --local=<folder> | --{npm,pypi,rubygems}=<package_name>)
 	 [--checks=check1,...] [--show-details]`
 	scorecardShort = "Security Scorecards"
 )

options/flags.go

@@ -73,7 +73,7 @@ func (o *Options) AddFlags(cmd *cobra.Command) {
 		&o.Repo,
 		FlagRepo,
 		o.Repo,
-		"repository to check",
+		"repository to check (valid inputs: \"owner/repo\", \"github.com/owner/repo\", \"https://github.com/repo\")",
 	)
 
 	cmd.Flags().StringVar(