[infra] upgrade upstream recipes-py dep to "main".

Also, I need to poke ci builders after another "main" fix
in https://crrev.com/i/3813486

R=phosek

Bug: chromium:1205320
Change-Id: I9894af0557f7d387f1f65315bccfd0a731b00dfc
Reviewed-on: https://gn-review.googlesource.com/c/gn/+/11461
Reviewed-by: Petr Hosek <phosek@google.com>
Commit-Queue: Petr Hosek <phosek@google.com>

infra/config/recipes.cfg

diff --git a/infra/config/recipes.cfg b/infra/config/recipes.cfg
index 77f7e99..4596382 100644
--- a/infra/config/recipes.cfg
+++ b/infra/config/recipes.cfg
@@ -2,7 +2,7 @@
   "api_version": 2,
   "deps": {
     "recipe_engine": {
-      "branch": "master",
+      "branch": "main",
       "revision": "d31ba13ede8c21e60116ae61e4490d53ba77fcbd",
       "url": "https://chromium.googlesource.com/infra/luci/recipes-py"
     }