Fix RustDesk slug in json (#2411)

Author: tremor021

json/rustdeskserver.json

@@ -1,6 +1,6 @@
 {
     "name": "RustDesk Server",
-    "slug": "rustdesk-server",
+    "slug": "rustdeskserver",
     "categories": [
         21
     ],
@@ -36,4 +36,4 @@
             "type": "info"
         }
     ]
-}
+}