chore(n8n): license the node under Apache-2.0 to match the monorepo

Every other publishable integration (@mem0/pi-agent-plugin,
@mem0/openclaw-mem0, @mem0/vercel-ai-provider) and the repo root ship
Apache-2.0. The n8n node carried MIT from the n8n starter template.

LICENSE is now byte-identical to integrations/pi-agent-plugin/LICENSE.

eslint-plugin-n8n-nodes-base hard-codes MIT in
community-package-json-license-not-default, so that rule is disabled.
It is a starter-template convention, not a functional requirement: n8n
resolves and loads community packages without reading the license field,
and n8n's own node packages (n8n-nodes-base, @n8n/n8n-nodes-langchain)
publish as "SEE LICENSE IN LICENSE.md" rather than MIT.

integrations/n8n-nodes-mem0/package.json

@@ -10,7 +10,7 @@
     "agents",
     "llm"
   ],
-  "license": "MIT",
+  "license": "Apache-2.0",
   "homepage": "https://mem0.ai",
   "author": {
     "name": "Mem0",