Update version number for new 3.4.0 release (#1529)

# why
Launch day!
# what changed

# test plan


<!-- This is an auto-generated description by cubic. -->
---
## Summary by cubic
Bump @browserbasehq/stagehand-server version from 3.3.0 to 3.4.0 to
publish the new release. No code or runtime changes.

<sup>Written for commit 24b5aff.
Summary will update on new commits.</sup>

<!-- End of auto-generated description by cubic. -->

Author: monadoid

packages/server/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@browserbasehq/stagehand-server",
-  "version": "3.3.0",
+  "version": "3.4.0",
   "description": "Stagehand API server",
   "type": "module",
   "private": true,