Add .vscode to .gitignore

These folders can be created to store local settings.

BUG=None
TEST=.vscode content does not appear with `git status`

Change-Id: I7b6c1b1bdb93ecbadc6e25b5fe9c9ecdbb4a3f0c
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/2842604
Tested-by: Alexandre Courbot <acourbot@chromium.org>
Tested-by: kokoro <noreply+kokoro@google.com>
Auto-Submit: Alexandre Courbot <acourbot@chromium.org>
Commit-Queue: Keiichi Watanabe <keiichiw@chromium.org>
Reviewed-by: Keiichi Watanabe <keiichiw@chromium.org>

.gitignore

diff --git a/.gitignore b/.gitignore
index 1acdbc7..bfe7471 100644
--- a/.gitignore
+++ b/.gitignore
@@ -7,3 +7,4 @@
 !/Cargo.lock
 lcov.info
 .idea
+.vscode