Build/Test Tools: Pin Importer plugin version for PHP < 7.2.

The WordPress Importer plugin now requires PHP 7.2 or higher. The plugin’s unit tests were removed as of [59769] in favor of running only within the plugin’s repository on GitHub instead.

[59769] was made during the 6.8 release cycle, so all WP <= 6.7 branches still checkout the latest revision for the plugin before running the PHPUnit test suite.

This change modifies the `env:install` script to download version `0.9.0` of the plugin (which is the last version of the Importer plugin that supports PHP < 7.2) when a qualifying version is being tested.

Merges [60748] to the 5.7 branch.

Props @swissspidy.
See #63983.

git-svn-id: https://develop.svn.wordpress.org/branches/5.7@60757 602fd350-edb4-49c9-b593-d223f7449a82

Author: desrosj

tools/local-env/scripts/install.js

@@ -54,6 +54,11 @@ function wp_cli( cmd ) {
 function install_wp_importer() {
 	const testPluginDirectory = 'tests/phpunit/data/plugins/wordpress-importer';
 
+
+	// The final version of the WordPress Importer plugin with support for PHP < 7.2 is 0.9.0.
+	const phpVersion = parseFloat(process.env.LOCAL_PHP.split('-')[0]);
+	const branchFlag = phpVersion < 7.2 ? '--branch 0.9.0' : '';
+
 	execSync( `docker compose exec -T php rm -rf ${testPluginDirectory}`, { stdio: 'inherit' } );
-	execSync( `docker compose exec -T php git clone https://github.com/WordPress/wordpress-importer.git ${testPluginDirectory} --depth=1`, { stdio: 'inherit' } );
+	execSync( `docker compose exec -T php git clone ${branchFlag} https://github.com/WordPress/wordpress-importer.git ${testPluginDirectory} --depth=1`, { stdio: 'inherit' } );
 }