support puppeteer v9

[michael-siek]

puppeteer is currently at v9 and the peerdependency for @axe-core/puppeteer is at v6 we should support the latest version of puppeteer.

[padmavemulapati]

When simply installed puppeteer - its installing puppeteer@5.5.0 , but installed puppeteer@latest - it installed

> puppeteer@9.1.1 install C:\Users\DQ_Padmavathi\Desktop\npmcore\axe-core-npm\packages\puppeteer\node_modules\puppeteer
> node install.js

Downloading Chromium r869685 - 155.9 Mb [====================] 100% 0.0s

and example file executed and got the expected results with puppeteer@9.1.1

[michael-siek]

Closing no docs required.