[recipes.cfg] upgrade to api_version 2

Bug:

Change-Id: I66060bbf29a5940041eecfac70df6dae0894887f
Reviewed-on: https://chromium-review.googlesource.com/462595
Commit-Queue: Robbie Iannucci <iannucci@chromium.org>
Reviewed-by: Nodir Turakulov <nodir@chromium.org>

infra/config/recipes.cfg

 {
-  "api_version": 1,
-  "deps": [
-    {
+  "api_version": 2,
+  "deps": {
+    "recipe_engine": {
       "branch": "master",
-      "project_id": "recipe_engine",
       "revision": "e77477ba61ef082e2e34d58fd1251a1cb707f698",
       "url": "https://chromium.googlesource.com/external/github.com/luci/recipes-py.git"
     }
-  ],
+  },
   "project_id": "depot_tools",
   "recipes_path": "recipes"
-}
+}
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