isValidPubPackageName function
Returns true when the name is a valid pub package name according to https://dart.dev/tools/pub/pubspec#name
The name should be all lowercase, with underscores to separate words,
just_like_this.
Use only basic Latin letters and Arabic digits: a-z0-9_
.
Also, make sure the name is a valid Dart identifier—that it doesn’t
start with digits and isn’t a reserved word (keyword).
Implementation
bool isValidPubPackageName(String name) {
return _cliNameRegExp.hasMatch(name) && !_keywords.contains(name);
}