doc: reserve NMV 139 for Electron 38

PR-URL: #58779
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Chengzhong Wu <legendecas@gmail.com>

Author: clavin

doc/abi_version_registry.json

@@ -1,5 +1,6 @@
 {
   "NODE_MODULE_VERSION": [
+    { "modules": 139,"runtime": "electron", "variant": "electron",             "versions": "38" },
     { "modules": 138,"runtime": "node",     "variant": "v8_13.7",              "versions": "25.0.0-pre" },
     { "modules": 137,"runtime": "node",     "variant": "v8_13.6",              "versions": "24.0.0" },
     { "modules": 136,"runtime": "electron", "variant": "electron",             "versions": "37" },