Reland "Add protobuf-py2_py3 3.13.0 to .vpython."

This is a reland of 9b53c2983260a210ba4f04510759bc56d5a2285e

It looks like the idea was correct (see [1]), changes with respect to
the original at [2].

[1] - https://chromium-review.googlesource.com/c/chromium/src/+/2545204/7/tools/privacy_budget/blink_apis/generate_blink_api_db.py
[2] - https://webrtc-review.googlesource.com/c/src/+/194261/1..2

Original change's description:
> Add protobuf-py2_py3 3.13.0 to .vpython.
>
> Starting from https://webrtc-review.googlesource.com/c/src/+/194081,
> WebRTC's protobuf are using version 3.13.0.1+ but when running on
> bots, we see errors that are probably caused by a version mismatch, see
> https://ci.chromium.org/p/webrtc/builders/perf/Perf%20Linux%20Trusty/4597.
>
> This CL updates WebRTC's .vpython to use protobuf 3.13.0.
>
> TBR=kwiberg@webrtc.org
>
> No-Try: True
> Bug: None
> Change-Id: I6bc5e71bacc67dbd9299a9588ddf826778451949
> Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/194143
> Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
> Reviewed-by: Andrey Logvin <landrey@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#32642}

TBR=kwiberg@webrtc.org

No-Try: True
No-Presubmit: True
Bug: None
Change-Id: Ic61d477b7ad104d15edf4afbbfb9c51f261bc435
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/194261
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#32649}
diff --git a/.vpython b/.vpython
index e8dc8e2..92c9c51 100644
--- a/.vpython
+++ b/.vpython
@@ -67,6 +67,10 @@
   version: "version:2.0.0"
 >
 wheel: <
+  name: "infra/python/wheels/protobuf-py2_py3"
+  version: "version:3.13.0"
+>
+wheel: <
   name: "infra/python/wheels/requests-py2_py3"
   version: "version:2.13.0"
 >