docs: add Chrome for Testing to main README

[MikeMcC399]

Situation

As noted in the Cypress documentation:

• cypress@14.4.0 changelog
• API > Node Events > before:browser:launch > Add browser extensions

• Chrome-branded browsers (e.g., standard Chrome) version 137 and above no longer support extension loading via this API, due to the removal of the --load-extension flag by Chrome. We recommend using Chrome for Testing or Chromium instead. See Cypress Docker image examples for Chrome for Testing and Chromium.

In the Cypress Docker images main README:

• "Chrome for Testing" is not mentioned
• "Chromium" is described in the Browsers sub-section Debian packages together with "Firefox ESR"

Change

Add a "Chrome for Testing" sub-section to the Browsers section in the main README document.

[cypress-app-bot]

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