use bazel --batch for release script (#1352)
use bazel --batch for release script (#1352)

Automatic merge from submit-queue.

use bazel --batch for release script

**What this PR does / why we need it**:

Follow up on #1223, bazel server consumes more memory while it doesn't provide benefits in CI.
This will make postsubmit more stable.

**Release note**:
```release-note
None
```
lizan/proxy,istio/proxy,lizan/proxy,lizan/proxy,istio/proxy,lizan/proxy,istio/proxy,istio/proxy