ESLint error: ES6 static methods not allowed

## Version

* Phaser Version: 3.87.0

## Description

```
phaser/src/cameras/2d/Camera.js
  504:62  error  ES6 static methods not allowed: Number.isInteger  es5/no-es6-static-methods
  504:89  error  ES6 static methods not allowed: Number.isInteger  es5/no-es6-static-methods
```
