by Anthony Fu @antfu
snake_case 文字列を camelCase に変換する CamelCase <T> を実装します。
例えば
type camelCase1 = CamelCase<'hello_world_with_types'> // expected to be 'helloWorldWithTypes'
type camelCase2 = CamelCase<'HELLO_WORLD_WITH_TYPES'> // expected to be same as previous one
