ColorizeAnimatedText's animation is weird.

the color animation is weird. There has a short animation at the beginning when repeated.

dependencies:
`animated_text_kit: ^4.2.0`

Here's a piece of code:

```dart
child: AnimatedTextKit(
repeatForever: true,
animatedTexts: [
ColorizeAnimatedText(
'市井小民',
speed: Duration(milliseconds: 1000),
textStyle: TextStyle(
fontSize: 24.0,
),
colors: [
Colors.purple,
Colors.blue,
Colors.yellow,
Colors.red,
],
),
],
)),
```

Please wait until repeated, about 10s.

Thanks for every tip!