test(angular): add support for multi-version testing (#25665)

angular/test/base/cypress/plugins/index.js

@@ -0,0 +1,22 @@
+/// <reference types="cypress" />
+// ***********************************************************
+// This example plugins/index.js can be used to load plugins
+//
+// You can change the location of this file or turn off loading
+// the plugins file with the 'pluginsFile' configuration option.
+//
+// You can read more here:
+// https://on.cypress.io/plugins-guide
+// ***********************************************************
+
+// This function is called when a project is opened or re-opened (e.g. due to
+// the project's config changing)
+
+/**
+ * @type {Cypress.PluginConfig}
+ */
+// eslint-disable-next-line no-unused-vars
+module.exports = (on, config) => {
+  // `on` is used to hook into various events Cypress emits
+  // `config` is the resolved Cypress config
+}