refactor: usage of node: for builtin modules

cli/commands/generate/challenge.ts

@@ -1,6 +1,5 @@
 import { Command, Option } from 'clipanion'
 import * as typanion from 'typanion'
-
 import chalk from 'chalk'
 
 import { Challenge } from '../../services/Challenge'

cli/commands/generate/solution.ts

@@ -1,6 +1,5 @@
 import { Command, Option } from 'clipanion'
 import * as typanion from 'typanion'
-
 import chalk from 'chalk'
 
 import { Solution } from '../../services/Solution'