Issue #3378779: purge_drush should have an extra.drush.services section in its composer.json.

modules/purge_drush/composer.json

+{
+  "name": "drupal/purge_drush",
+  "type": "drupal-module",
+  "description": "Provides a generic external cache invalidation API and queue service for DRUSH.",
+  "license": "GPL-2.0-or-later",
+  "authors": [
+    {
+      "name": "Niels van Mourik",
+      "homepage": "http://www.nielsvm.org"
+    }
+  ],
+  "extra": {
+    "branch-alias": {
+      "dev-8.x-3.x": "3.x-dev"
+    },
+    "drush": {
+      "services": {
+        "drush.services.yml": "^10 || ^11"
+      }
+    }
+  }
+}
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