fix version for composer 2

Author: pxpm

src/app/Console/Commands/Version.php

@@ -37,7 +37,28 @@ public function handle()
         $this->line('');
 
         $this->comment('### BACKPACK PACKAGE VERSIONS:');
-        foreach (\PackageVersions\Versions::VERSIONS as $package => $version) {
+
+        if (class_exists(\Composer\InstalledVersions::class, false)) {
+            $this->getPackageVersionsFromComposer2();
+        } else {
+            $this->getPackageVersionsFromComposer1();
+        }
+    }
+
+    private function getPackageVersionsFromComposer2()
+    {
+        $packages = \Composer\InstalledVersions::getInstalledPackages();
+        foreach ($packages as $package) {
+            if (substr($package, 0, 9) == 'backpack/') {
+                $this->line($package.': '.\Composer\InstalledVersions::getPrettyVersion($package));
+            }
+        }
+    }
+
+    private function getPackageVersionsFromComposer1()
+    {
+        $packages = \PackageVersions\Versions::VERSIONS;
+        foreach ($packages as $package => $version) {
             if (substr($package, 0, 9) == 'backpack/') {
                 $this->line($package.': '.strtok($version, '@'));
             }