Allow override of docker image tag
>>> [!note] Migrated issue
<!-- Drupal.org comment -->
<!-- Migrated from issue #3421873. -->
Reported by: [dimitriskr](https://www.drupal.org/user/3575407)
Related to !130
>>>
<h3 id="summary-problem-motivation">Problem/Motivation</h3>
<p>Currently the tag in the db/php service is set on "production", not allowing maintainers to switch to other tags for testing purposes</p>
<h4 id="summary-steps-reproduce">Steps to reproduce</h4>
<h3 id="summary-proposed-resolution">Proposed resolution</h3>
<p>Create a new variable DB/PHP_TAG or similar, with default value "production". I suggest doing this in core too.<br>
That will allow testing with images other than drupalci, since all settings will be completely overrideable</p>
<h3 id="summary-remaining-tasks">Remaining tasks</h3>
<h3 id="summary-ui-changes">User interface changes</h3>
<h3 id="summary-api-changes">API changes</h3>
<h3 id="summary-data-model-changes">Data model changes</h3>
issue