Add cv2 wheel

Adds the opencv_python wheel for use in Python 3 so that Telemetry can
import cv2. This will allow the GPU pixel tests to use the numpy/cv2
codepath for PNG manipulation, which should revert runtimes back to what
they were under Python 2. The switch to the fallback pure Python
implementation caused image creation to take ~4.5 seconds, which ended
up more than doubling the total test runtime.

Won't have any effect until the Telemetry-side CL lands
crrev.com/c/3651191.

Bug: 1320069
Change-Id: I43081fac43770252a6054bb6f7e83df1508b0c00
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3651402
Reviewed-by: Robbie Iannucci <iannucci@chromium.org>
Commit-Queue: Brian Sheedy <bsheedy@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1004472}

.vpython3

@@ -169,6 +169,14 @@ wheel: <
     platform: "linux_aarch64"
   >
 >
+wheel: <
+  name: "infra/python/wheels/opencv_python/${vpython_platform}"
+  version: "version:4.5.3.56.chromium.4"
+  # There is currently no Linux arm/arm64 version in CIPD.
+  not_match_tag <
+    platform: "linux_aarch64"
+  >
+>
 
 # Used by various python unit tests.
 wheel: <