chatqna k8s manifest: Fixed retriever-redis v0.9 image issue

[lianhao]

Description

chatqna k8s manifest: Fixed retriever-redis v0.9 image issue.

Issues

n/a.

Type of change

List the type of change like below. Please delete options that are not relevant.

• [x] Bug fix (non-breaking change which fixes an issue)

Dependencies

n/a.

Tests

manually tested.

[lianhao]

The test fails because of issue #636, but we need it to land in v0.9 release