pkg/plugins/plugins.go: remove ineffective break statement.

See,
$ gometalinter --vendor --deadline 10m --disable-all --enable=megacheck ./...
pkg/plugins/plugins.go:124:4:warning: ineffective break statement. Did you mean to break out of the outer loop? (SA4011) (megacheck)

pkg/plugins/plugins.go

@@ -121,7 +121,6 @@ func (pm *PluginManager) Run(ctx context.Context) error {
 			pm.checkForUpdates()
 		case <-ctx.Done():
 			run = false
-			break
 		}
 	}