Bump version to 8.5.6

Author: tmacro

package.json

@@ -3,7 +3,7 @@
   "engines": {
     "node": ">=20"
   },
-  "version": "8.5.5",
+  "version": "8.5.6",
   "description": "Client library and binary for Vault, the user directory and key management service",
   "main": "index.js",
   "repository": "scality/vaultclient",