fix: use only Node.js 20.x and add type: module for ESLint

- Remove Node.js 18.x from CI matrix
- Add type: module to package.json for ESLint config

Author: vieiraricardo

.github/workflows/ci-cd.yml

@@ -12,7 +12,7 @@ jobs:
 
     strategy:
       matrix:
-        node-version: [18.x, 20.x]
+        node-version: [20.x]
 
     steps:
       - uses: actions/checkout@v4

package.json

@@ -2,6 +2,7 @@
   "name": "@superdapp/agents",
   "version": "1.0.2",
   "description": "SuperDapp AI Agents SDK and CLI for Node.js/TypeScript",
+  "type": "module",
   "main": "dist/index.js",
   "types": "dist/index.d.ts",
   "bin": {
@@ -78,4 +79,4 @@
     "url": "https://github.com/SuperDappAI/superdapp-js/issues"
   },
   "homepage": "https://github.com/SuperDappAI/superdapp-js#readme"
-}
+}