Remove unnecessary npm self-upgrade from release workflow

The bundled npm on Node 22.22.2 runners is broken (missing promise-retry),
causing `npm install -g npm@latest` to fail. The default npm from
actions/setup-node is sufficient for publish.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: teallarson

.github/workflows/release.yml

@@ -24,7 +24,6 @@ jobs:
         with:
           node-version: 22
           registry-url: "https://registry.npmjs.org"
-      - run: npm install -g npm@latest
       - run: bun install
 
       - name: Check if version changed

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@arcadeai/create-agent",
-  "version": "0.5.2",
+  "version": "0.5.3",
   "type": "module",
   "description": "Scaffold an Arcade-powered AI agent",
   "license": "MIT",