Rely on the PR template for docs/code consistency [#12]

These comments were a reasonable attempt at ensuring the documentation
matched reality, but the checkbox in the pull request template is much
more likely to produce results.

internal/helm/plan.go

@@ -69,7 +69,6 @@ func determineSteps(cfg Config) *func(Config) []Step {
 		return &help
 	default:
 		switch cfg.DroneEvent {
-		// Note: These events are documented in docs/upgrade_settings.yml. Any changes here should be reflected there.
 		case "push", "tag", "deployment", "pull_request", "promote", "rollback":
 			return &upgrade
 		case "delete":