Add python grpc to .vpython3 for ios test runner

Bug: b/247047419
Change-Id: I3dad5037cfd91c55838db0144138a151edcbe870
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/275760
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Commit-Queue: Christoffer Jansson <jansson@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#38099}
diff --git a/.vpython3 b/.vpython3
index 346486e..31a2c59 100644
--- a/.vpython3
+++ b/.vpython3
@@ -56,6 +56,12 @@
   >
 >
 
+# GRPC used by iOS test.
+wheel: <
+  name: "infra/python/wheels/grpcio/${vpython_platform}"
+  version: "version:1.44.0"
+>
+
 wheel: <
   name: "infra/python/wheels/six-py2_py3"
   version: "version:1.15.0"