Enable unit test integration for vscode users.

.vscode folder will be picked up for every vscode that opens this project, and the config makes it so that tests are ran with vpython3.

Change-Id: Ide0566287dde36b914dd55053daba4d36a6a6964
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/7262695
Commit-Queue: Alex Ovsienko <ovsienko@google.com>
Reviewed-by: Junji Watanabe <jwata@google.com>
Reviewed-by: Scott Lee <ddoman@chromium.org>

.vscode/settings.json

@@ -0,0 +1,11 @@
+{
+    "python.testing.unittestEnabled": true,
+    "python.testing.pytestEnabled": true,
+    "python.testing.unittestArgs": [
+        "-s",
+        "./tests",
+        "-p",
+        "*_test.py"
+    ],
+    "python.defaultInterpreterPath": "vpython3"
+}