ci: Pin Drupal core to latest security releases + PHPStan 2.1.48 release
>>> [!note] Migrated issue
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<!-- Migrated from issue #3585060. -->
Reported by: [penyaskito](https://www.drupal.org/user/959536)
Related to !924
>>>
<h3 id="overview">Overview</h3>
<pre>No composer.lock file present. Updating dependencies to latest instead of installing from lock file. See https://getcomposer.org/install for more information.<br>Loading composer repositories with package information<br>Updating dependencies<br>Your requirements could not be resolved to an installable set of packages.<br> Problem 1<br> - Root composer.json requires drupal/core-recommended 11.3.6 -> satisfiable by drupal/core-recommended[11.3.6].<br> - drupal/core-recommended 11.3.6 requires drupal/core 11.3.6 -> found drupal/core[11.3.6] but these were not loaded, because they are affected by security advisories ("SA-CORE-2026-001", "SA-CORE-2026-003", "SA-CORE-2026-002"). Go to https://packagist.org/security-advisories/ to find advisory details. To ignore the advisories, add them to the audit "ignore" config. To turn the feature off entirely, you can set "block-insecure" to false in your "audit" config.</pre><p>after today's security releases.</p>
<h3 id="proposed-resolution">Proposed resolution</h3>
<p>Pin Drupal core to latest security releases.<br>
Also: <a href="https://github.com/phpstan/phpstan/releases/tag/2.1.48">PHPStan 2.1.48</a> release 29 minutes ago.</p>
<h3 id="ui-changes">User interface changes</h3>
issue