add RNV source

Author: metrophil

sources.json

@@ -814,6 +814,20 @@
             }
         ]
     },
+    {
+        "shortOperatorName": "vrn-rnv-tram",
+        "contributors": [
+            {
+                "github": "metrophil"
+            }
+        ],
+        "sources": [
+            {
+                "name": "Liniennetz regulär Schiene RNV",
+                "source": "https://www.rnv-online.de/media/rnv-online.de/Fahrtinfo/Liniennetzplaene/regulaer/Liniennetzplan_Schiene.pdf"
+            }
+        ]
+    },
     {
         "shortOperatorName": "vrn-sbahn-rn",
         "contributors": [