Automatic merge from submit-queue (batch tested with PRs 60302, 57921, 59042, 60126, 59561). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

[fluentd-gcp addon] Update event-exporter

Update to new version of event-exporter which includes bugfix for metrics
https://github.com/GoogleCloudPlatform/k8s-stackdriver/releases/tag/event-exporter-v0.1.8

```release-note
[fluentd-gcp addon] Fixed bug with reporting metrics in event-exporter
```