Update node version for undici proxy support

Author: parkerbxyz

.github/workflows/release.yml

@@ -22,7 +22,7 @@ jobs:
 
       - uses: actions/setup-node@v4
         with:
-          node-version-file: .node-version
+          node-version-file: package.json
           cache: 'npm'
 
       - run: npm ci

.node-version

@@ -4,6 +4,9 @@
   "type": "module",
   "version": "1.10.3",
   "description": "GitHub Action for creating a GitHub App Installation Access Token",
+  "engines": {
+    "node": ">=20.16.0 <21"
+  },
   "scripts": {
     "build": "esbuild main.js post.js --bundle --outdir=dist --out-extension:.js=.cjs --platform=node --target=node20 --packages=bundle",
     "test": "c8 --100 ava tests/index.js",