Update dependency zx to v8 (#2829)

Co-authored-by: elastic-renovate-prod[bot] <174716857+elastic-renovate-prod[bot]@users.noreply.github.com>

Author: elastic-renovate-prod[bot]

package.json

@@ -88,7 +88,7 @@
     "typescript": "5.8.3",
     "workq": "3.0.0",
     "xmlbuilder2": "3.1.1",
-    "zx": "7.2.3"
+    "zx": "8.5.4"
   },
   "dependencies": {
     "@elastic/transport": "^9.0.1",