Roll recipe dependencies (trivial).

This is an automated CL created by the recipe roller. This CL rolls recipe
changes from upstream projects (depot_tools) into this repository.

depot_tools:
  https://crrev.com/780e6bf8d43870389e6eba66611c7f25c8e0f6f3 (ehmaldonado@google.com)
    gclient: Allow setting GCLIENT_PY3 to 0 to run on Python 2.

More info is at https://goo.gl/zkKdpD. Use https://goo.gl/noib3a to file a bug.

TBR=borenet@google.com

Recipe-Tryjob-Bypass-Reason: Autoroller
Bugdroid-Send-Email: False
Change-Id: Id413142efe7727125fcea3e4ec0b4f7bf3306f9f
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/273920
Reviewed-by: Recipe Roller <recipe-mega-autoroller@chops-service-accounts.iam.gserviceaccount.com>
Commit-Queue: Recipe Roller <recipe-mega-autoroller@chops-service-accounts.iam.gserviceaccount.com>

Author: recipe-roller

infra/config/recipes.cfg

@@ -14,7 +14,7 @@
   "deps": {
     "depot_tools": {
       "branch": "master",
-      "revision": "7552630e0d993ba7faf727392f2bfaaec19a7bfb",
+      "revision": "780e6bf8d43870389e6eba66611c7f25c8e0f6f3",
       "url": "https://chromium.googlesource.com/chromium/tools/depot_tools.git"
     },
     "recipe_engine": {