fix: add srCheckPassword param to support new postgresql-ha stream replication check requirements (#894)

### Add new 'srCheckPassword' postgresql-ha value to support new postgresql-ha stream replication check requirements

Per Bitnami's [documentation](https://github.com/bitnami/charts/tree/main/bitnami/postgresql-ha#to-1600), a new 'sr_check_user' now exists for the purpose of pgpool preforming stream replication checking.

### Benefits

This change allows customizing that role's password by overriding Bitnami's chart value.

### Possible drawbacks

None that I'm aware of.

### Applicable issues

- Fixes #888

### Additional information

Per #888, the Bitnami PR where customizable stream reapplication check credentials were introduced is https://github.com/bitnami/charts/pull/33552

### Checklist

<!-- [Place an '[X]' (no spaces) in all applicable fields. Please remove unrelated fields.] -->

- [x] Parameters are documented in the `values.yaml` and added to the `README.md` using [readme-generator-for-helm](https://github.com/bitnami-labs/readme-generator-for-helm)
- [x] Helm templating unittests are added (required when changing anything in `templates` folder)

Reviewed-on: https://gitea.com/gitea/helm-gitea/pulls/894
Reviewed-by: pat-s <pat-s@noreply.gitea.com>
Co-authored-by: Jade Deane <jade.deane@gmail.com>
Co-committed-by: Jade Deane <jade.deane@gmail.com>

README.md

@@ -1167,6 +1167,7 @@ Valkey and [Valkey cluster](#valkey-cluster) cannot be enabled at the same time.
 | `postgresql-ha.postgresql.repmgrPassword`   | Repmgr Password                                                  | `changeme2` |
 | `postgresql-ha.postgresql.postgresPassword` | postgres Password                                                | `changeme1` |
 | `postgresql-ha.pgpool.adminPassword`        | pgpool adminPassword                                             | `changeme3` |
+| `postgresql-ha.pgpool.srCheckPassword`      | pgpool srCheckPassword                                           | `changeme4` |
 | `postgresql-ha.service.ports.postgresql`    | PostgreSQL service port (overrides `service.ports.postgresql`)   | `5432`      |
 | `postgresql-ha.persistence.size`            | PVC Storage Request for PostgreSQL HA volume                     | `10Gi`      |