feat: modify the branch to 2.5 (#3274)

Modify branch to 2.5 for doc purposes.

Signed-off-by: suzhou <[email protected]>

Author: SuZhou-Joe

package.json

@@ -12,7 +12,7 @@
   ],
   "private": true,
   "version": "2.5.0",
-  "branch": "2.x",
+  "branch": "2.5",
   "types": "./opensearch_dashboards.d.ts",
   "tsdocMetadata": "./build/tsdoc-metadata.json",
   "build": {