Revert "[artifacts] Switch to OAUTH GCS FullControl scope."

This reverts commit d9d7a8abffd5cfbedf5881fceff45176e0c284ab.

Reason for revert: Should be unnecessary after the token server changes in https://chrome-internal-review.googlesource.com/c/infradata/config/+/1123383

Original change's description:
> [artifacts] Switch to OAUTH GCS FullControl scope.
> 
> This is the scope the luci-token-server has whitelisted for this role.
> 
> Change-Id: I964dc3e5876152e209eb15cf7891198931297f0d

TBR=joshuaseaton@google.com,nmulcahey@google.com

Change-Id: I3e96687e5462d807fbac1db660b1e10c937fda59
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
diff --git a/artifacts/artifacts.go b/artifacts/artifacts.go
index 1499d0a..f77dd02 100644
--- a/artifacts/artifacts.go
+++ b/artifacts/artifacts.go
@@ -20,7 +20,7 @@
 
 // NewClient creates a new Client.
 func NewClient(ctx context.Context, opts auth.Options) (*Client, error) {
-	opts.Scopes = append(opts.Scopes, storage.ScopeFullControl)
+	opts.Scopes = append(opts.Scopes, storage.ScopeReadWrite)
 	client, err := gcs.NewClient(ctx, opts)
 	if err != nil {
 		return nil, err