GitHub Status notifications error

Hi,
I've got GitHub `checkRun` notification defined, as in docs:
```yaml
template.app-deployed: |
...
github:
checkRun:
name: "continuous-delivery/{{.app.metadata.name}}"
details_url: "{{.context.argocdUrl}}/applications/{{.app.metadata.name}}?operation=true"
status: completed
conclusion: success
started_at: "YYYY-MM-DDTHH:MM:SSZ"
completed_at: "YYYY-MM-DDTHH:MM:SSZ"
output:
title: "Deployment of {{.app.metadata.name}} on ArgoCD"
summary: "Application {{.app.metadata.name}} is now running new version of deployments manifests."
text: |
Application {{.app.metadata.name}} is now running new version of deployments manifests.
See more here: {{.context.argocdUrl}}/applications/{{.app.metadata.name}}?operation=true
```

However in notifications-controller logs I can see that the call to the GitHub API was unsuccessful:
```
Failed to notify recipient {github } defined in resource argocd/panel-staging: POST https://api.github.com/repos/xxx/infra-panel/check-runs: 422 Validation Failed [{Resource:CheckRun Field:conclusion Code:missing_field Message:}] using the configuration in namespace argocd
```

Seems like some bug.

Start from the notifications-controller GitHub checkRun path and reproduce the POST to /repos/xxx/infra-panel/check-runs using the YAML shown in the issue. Compare the generated request with GitHub's required CheckRun fields, especially conclusion, and verify the corrected request is accepted without the 422 validation error.

Written by the indexing model from the issue text.