THRIFT-4990 Switch to .NET core 3.0
Client: netstsd
Patch: Jens Geyer

This closes #1909
diff --git a/tutorial/netstd/Server/Program.cs b/tutorial/netstd/Server/Program.cs
index 25e7dae..e1dab01 100644
--- a/tutorial/netstd/Server/Program.cs
+++ b/tutorial/netstd/Server/Program.cs
@@ -346,7 +346,7 @@
 
             public class Startup
             {
-                public Startup(IHostingEnvironment env)
+                public Startup(IWebHostEnvironment env)
                 {
                     var builder = new ConfigurationBuilder()
                         .SetBasePath(env.ContentRootPath)
@@ -366,7 +366,7 @@
                 }
 
                 // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
-                public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
+                public void Configure(IApplicationBuilder app, IWebHostEnvironment env, ILoggerFactory loggerFactory)
                 {
                     app.UseMiddleware<THttpServerTransport>();
                 }