ci: run next.js repo e2e tests on node 18.18.0

The minimum supported version for canary got bumped recently.

We could use different versions per next.js version but it probably isn't worth it here.

Author: serhalp

.github/workflows/test-e2e.yml

@@ -19,7 +19,7 @@ concurrency:
   cancel-in-progress: true
 
 env:
-  NODE_VERSION: 18.17.1
+  NODE_VERSION: 18.18.0
   PNPM_VERSION: 8.9.0
   NEXT_REPO: vercel/next.js
   NEXT_TEST_MODE: deploy