Updated key/endpoint

Endpoints are not region-based anymore, but rather custom domain -based. Although regional endpoints will still work. Also, the authentication information is moving to a standard of getting it from environment variables.

Author: wiazur

dotnet/Search/BingEntitySearchv7.cs

@@ -6,13 +6,13 @@ namespace EntitySearchSample
 {
     class Program
     {
-        static string host = "https://api.cognitive.microsoft.com";
+        static string host = Environment.GetEnvironmentVariable("BING_ENTITY_SEARCH_ENDPOINT"); 
         static string path = "/bing/v7.0/entities";
 
         static string market = "en-US";
 
         // NOTE: Replace this example key with a valid subscription key.
-        static string key = "ENTER YOUR KEY HERE";
+        static string key = Environment.GetEnvironmentVariable("BING_ENTITY_SEARCH_SUBSCRIPTION_KEY");
 
         static string query = "italian restaurant near me";
 
@@ -38,4 +38,4 @@ static void Main(string[] args)
         }
 
     }
-}
+}