build: Update wasi-vfs to 0.5.0

0.5.0 includes a fix for WASI SDK 20.0 + reactor

Author: kateinoigakukun

lib/ruby_wasm/build/product/wasi_vfs.rb

@@ -2,7 +2,7 @@
 
 module RubyWasm
   class WasiVfsProduct < BuildProduct
-    WASI_VFS_VERSION = "0.4.0"
+    WASI_VFS_VERSION = "0.5.0"
 
     def initialize(build_dir)
       @build_dir = build_dir