CI: also test against next minor: 11.2.x aka Drupal 11.x HEAD

Necessary to not fall behind Drupal core HEAD, see #3495129-12: Add `toArray()` method to prop sources for the first symptom.

Anybody can do this: XB is just using the standard GitLab CI template from https://www.drupal.org/project/gitlab_templates 😄

This MR will need to make this change, among others:

diff --git a/phpstan.neon b/phpstan.neon
index 37ccc1a0..e2882965 100644
--- a/phpstan.neon
+++ b/phpstan.neon
@@ -9,12 +9,11 @@ parameters:
     - profile
   excludePaths:
     - modules/xb_vite
-    - modules/same_page_preview
     # These are 1:1 copies from Drupal core, with trivial additions that cannot have significant PHPStan impact. PHPStan compliance should happen upstream.
     - src/Plugin/DataTypeOverride
     - src/Plugin/Field/FieldTypeOverride
     # The npm package flatted includes PHP files 🙃
-    - tests/src/Cypress/node_modules
+    - tests/src/Cypress/node_modules?
     - ui/node_modules
     # This trait decorates core's \Drupal\Core\Test\FunctionalTestSetupTrait::prepareSettings(), which itself triggers a PHPStan warning that core ignores. Match that.
     - tests/src/Traits/ContribStrictConfigSchemaTestTrait.php

+1

#3495655: CI: update template for Drupal 11.1.0 landed.

Crediting Lee here for his review over there that relates to the scope of this issue.

Well spotted!