feat(cli): remove validation for --coverage-report

this allows for custom nyc coverage report packages to be used

PR-URL: #817
Credit: @ahmadnassri
Close: #817
Reviewed-by: @isaacs

bin/jack.js

@@ -376,7 +376,6 @@ Much more documentation available at: https://www.node-tap.org/
 
  'coverage-report': list({
  hint: 'type',
- valid: nycReporters,
  description: `Output coverage information using the
  specified istanbul/nyc reporter type.
 
@@ -390,7 +389,7 @@ Much more documentation available at: https://www.node-tap.org/
  This can be run on its own at any time
  after a test run that included coverage.
 
- Available NYC reporters:
+ Built-in NYC reporters:
  ${nycReporters.join(' ')}`,
  }),