Compatibility with Composer 2.2 for composer-plugin

[remicollet]

With composer 2.2

composer/package-versions-deprecated contains a Composer plugin which is currently not in your allow-plugins config. See https://getcomposer.org/allow-plugins
Do you trust "composer/package-versions-deprecated" to execute code and wish to enable it now? (writes "allow-plugins" to composer.json) [y,n,d,?] y

If accepted, changes in compooser.json

diff --git a/composer.json b/composer.json
index 06575ebe..e22cc319 100644
--- a/composer.json
+++ b/composer.json
@@ -60,6 +60,9 @@
     "minimum-stability": "dev",
     "prefer-stable": true,
     "config": {
-        "optimize-autoloader": true
+        "optimize-autoloader": true,
+        "allow-plugins": {
+            "composer/package-versions-deprecated": true
+        }
     }
 }

[llaville]

Info about Composer 2.2 (future) LTS: https://github.com/composer/composer/releases/tag/2.2.0-RC1