chore: bump asdf-vm/actions to v4 and add bin/download no-op to pass CI checks (#494)

* chore: bump asdf-vm/actions to v4 to fix build

* chore: add no-op download callback to pass plugin-test checks

Author: Stratus3D

.github/workflows/ci.yml

@@ -24,7 +24,7 @@ jobs:
     steps:
       - uses: actions/checkout@v6
       - name: Test plugin
-        uses: asdf-vm/actions/plugin-test@v3
+        uses: asdf-vm/actions/plugin-test@v4
         with:
           command: ruby -v
 

bin/download

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+
+# This download callback is no-op because ruby-build does not provide a way to
+# download Ruby without compiling or installing it.