[bazel] credential_helper flags is no longer experimental

Author: shs96c

.bazelrc

@@ -121,7 +121,7 @@ build:remote --action_env=PATH=/bin:/usr/bin:/usr/local/bin
 test:remote --test_env=HOME=/home/dev
 
 # Make sure we sniff credentials properly
-build:remote --experimental_credential_helper=%workspace%/scripts/credential-helper.sh
+build:remote --credential_helper=%workspace%/scripts/credential-helper.sh
 
 # Use pinned browsers when running remotely
 build:remote --//common:pin_browsers