Environment variables provider (#19)

created provider with environment variables list

samples/Basic/Startup.cs

@@ -31,7 +31,8 @@ public void ConfigureServices(IServiceCollection services)
                 .With<ClrVersionProvider>()
                 .With<AssemblyVersionProvider>()
                 .With<AppDomainAssembliesVersionProvider>()
-                .With<EnvironmentProvider>();
+                .With<EnvironmentProvider>()
+                .With<EnvironmentVariablesProvider>();
         }
 
         // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.

src/AspNetCore.VersionInfo/Providers/EnvironmentVariablesProvider.cs

@@ -0,0 +1,26 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace AspNetCore.VersionInfo.Providers
+{
+    public class EnvironmentVariablesProvider : IInfoProvider
+    {
+        public string Name => nameof(EnvironmentVariablesProvider);
+
+        public IDictionary<string, string> GetData()
+        {
+            var dict = new Dictionary<string, string>();
+
+            foreach (DictionaryEntry envVar in Environment.GetEnvironmentVariables())
+            {
+                dict.Add(envVar.Key.ToString(), envVar.Value.ToString());
+            }
+
+            return dict;
+        }
+    }
+}