Keycloak upgrade with monitoring fix

Big Bang

Update keycloak release tag and test-values and example configs.

Package Merge Request

Package Changes

• Keycloak patch upgrade from 20.0.2 to 20.0.3
• fixes for prometheus monitoring

Package MR

big-bang/product/packages/keycloak!97 (merged)

For Issue

Closes big-bang/product/packages/keycloak#81 (closed)