correct order for AddAzureTextCompletionService params in dotnet read…

…me (#974)

### Motivation and Context
dotnet README.md has incorrect order for parameters for
AddAzureTextCompletionService
Error message returns: "The Azure OpenAI endpoint must start with
'https://'" when following the read me.


### Description
Changed the order to reflect the constructor.

dotnet/README.md

@@ -27,10 +27,9 @@ var kernel = Kernel.Builder.Build();
 
 // Azure OpenAI
 kernel.Config.AddAzureTextCompletionService(
-    "davinci-azure",                     // Alias used by the kernel
     "text-davinci-003",                  // Azure OpenAI Deployment Name
     "https://contoso.openai.azure.com/", // Azure OpenAI Endpoint
-    "...your Azure OpenAI Key..."        // Azure OpenAI Key
+    "...your Azure OpenAI Key...",       // Azure OpenAI Key
 );
 
 // Alternative using OpenAI