prometheus-nginx-exporter: 0.5.0 -> 0.6.0 (#81285)

* prometheus-nginx-exporter: 0.5.0 -> 0.6.0

* nixos/prometheus-nginx-exporter: update for 0.6.0

Added new option constLabels and updated virtualHost name in the
exporter's test.

nixos/modules/services/monitoring/prometheus/exporters/nginx.nix

@@ -30,7 +30,17 @@ in
         Whether to perform certificate verification for https.
       '';
     };
-
+    constLabels = mkOption {
+      type = types.listOf types.str;
+      default = [];
+      example = [
+        "label1=value1"
+        "label2=value2"
+      ];
+      description = ''
+        A list of constant labels that will be used in every metric.
+      '';
+    };
   };
   serviceOpts = {
     serviceConfig = {
@@ -40,6 +50,7 @@ in
           --nginx.ssl-verify ${toString cfg.sslVerify} \
           --web.listen-address ${cfg.listenAddress}:${toString cfg.port} \
           --web.telemetry-path ${cfg.telemetryPath} \
+          --prometheus.const-labels ${concatStringsSep "," cfg.constLabels} \
           ${concatStringsSep " \\\n  " cfg.extraFlags}
       '';
     };