Playwright docker failing to find chromium

This started happening on our CI yesterday:

```
browserType.launch: Executable doesn't exist at /opt/pw-browsers/chromium-1080/chrome-linux/chrome
╔═════════════════════════════════════════════════════════════════════════╗
║ Looks like Playwright Test or Playwright was just installed or updated. ║
║ Please run the following command to download new browsers: ║
║ ║
║ yarn playwright install ║
║ ║
║ <3 Playwright Team ║
╚═════════════════════════════════════════════════════════════════════════╝
at module.exports.createPlaywrightBrowser (/usr/lib/node_modules/backstopjs/core/util/runPlaywright.js:43:42)
```

I ended up adding this to our Dockerfile to make it work temporarily:

```
RUN mkdir -p /opt/pw-browsers/chromium-1080/chrome-linux \
&& ln -s /usr/bin/chromium /opt/pw-browsers/chromium-1080/chrome-linux/chrome
```

I found this related https://github.com/garris/BackstopJS/issues/1468 but we're already on 6.2.2