feat(argo-cd): add support for passing redis - sentinel credentials

[shlomitubul]

This PR enables authentication for external Redis with Sentinel by introducing REDIS_SENTINEL_USERNAME and REDIS_SENTINEL_PASSWORD as optional environment variables. These credentials can now be passed via secrets to the controller, repo-server, and server templates, mirroring the approach used for standard external Redis connections.

NOTE: The actual support for username/password for Sentinel in argo code added in this PR: https://github.com/argoproj/argo-cd/pull/17168

Checklist:

• [x] I have bumped the chart version according to versioning
• [x] I have updated the documentation according to documentation
• [x] I have updated the chart changelog with all the changes that come with this pull request according to changelog.
• [x] Any new values are backwards compatible and/or have sensible default.
• [x] I have signed off all my commits as required by DCO.
• [x] My build is green (troubleshooting builds).

[yu-croco]

I have updated the chart changelog with all the changes that come with this pull request according to changelog.

Please handle this.

[shlomitubul]

@yu-croco @pdrastil is there anything else that needs to be changed/fixed?

[pdrastil]

@shlomitubul PR looks good, we are just waiting on upstream to cherry pick this into release branch

[github-actions[bot]]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[corradomatt]

Any updates on when this might be merged for release? I'm working on a deployment where I'd like to use Sentinel but it looks like this is a blocker to that.

[yu-croco]

Hi @corradomatt . As discussed https://github.com/argoproj/argo-helm/pull/2492#issuecomment-1973361762 , we are waiting for upstream that https://github.com/argoproj/argo-cd/pull/17168 is released as specific version. 🙋 We will merge this PR as soon as upstream is handled.