Fix usage for ESLint v9.0.0 or later

[mlahargou]

https://eslint.org/docs/latest/use/troubleshooting/v9-rule-api-changes

ESLint v9.0.0 introduces changes to the rules API that plugin rules use, which included moving some methods from the context object to the sourceCode object. If you’re seeing one of these errors, that means the plugin has not yet been updated to use the new rules API.

---

I'm getting the following error with this plugin on v9 of eslint:

TypeError: context.getScope is not a function
Occurred while linting /path/to/file.js:1
Rule: "es/no-regexp-lookbehind-assertions"