fix url prefix

Author: phnx47

src/Prometheus.Client.MetricServer/MetricServer.HttpListener.cs

@@ -62,7 +62,7 @@ public MetricServer(string host, int port, string url, bool useHttps)
         public MetricServer(string hostname, int port, string url, IEnumerable<IOnDemandCollector> standardCollectors, ICollectorRegistry registry, bool useHttps)
             : base(standardCollectors, registry)
         {
-            _httpListener.Prefixes.Add($"http{(useHttps ? "s" : "")}://{hostname}:{port}/{url}");
+            _httpListener.Prefixes.Add($"http{(useHttps ? "s" : "")}://{hostname}:{port}/{url}/");
         }
 
         /// <inheritdoc />

src/Prometheus.Client.MetricServer/Prometheus.Client.MetricServer.csproj

@@ -3,7 +3,7 @@
     <Description>MetricServer for the Prometheus.Client</Description>
     <Copyright>2017 © Sergey Kuznetsov</Copyright>
     <AssemblyTitle>Prometheus.Client.MetricServer</AssemblyTitle>
-    <VersionPrefix>1.2.0</VersionPrefix>
+    <VersionPrefix>1.2.1</VersionPrefix>
     <Authors>Sergey Kuznetsov</Authors>
     <TargetFrameworks>net45;netstandard1.3;netstandard2.0</TargetFrameworks>
     <AssemblyName>Prometheus.Client.MetricServer</AssemblyName>