Type mistmatch between return types of ValidateHelper and validate

[JamesLMilner]

Bug

There is currently a mismatch between the a commands .validate method and the ValidateHelper. .validate returns type of boolean but the ValidateHelper returns a Promise, meaning you can't use the helper in a command. Making .validate async would fix this issue.

Code

	validate(helper: Helper) {
		let schema;
		try {
			schema = JSON.parse(readFileSync(path.join(__dirname, 'schema.json')).toString());
		} catch (error) {
			return Promise.reject(Error('The dojorc schema for cli-build-app could not be read: ' + error));
		}
		return helper.validation.validate({
			commandGroup: command.group as string,
			commandName: command.name,
			commandSchema: schema,
			commandConfig: helper.configuration.get(),
			silentSuccess: true
		});
	}

Expected behavior:

You should be able to use the provided ValidateHelper in the .validate function.

Actual behavior:

ValidateHelper is async which stops it from being useable.