fix capitalization for .NET

Author: GitHubber17

articles/azure-app-configuration/TOC.yml

@@ -91,7 +91,7 @@
           href: https://go.microsoft.com/fwlink/?linkid=2074664
         - name: .NET Framework builder
           href: https://go.microsoft.com/fwlink/?linkid=2074663
-        - name: Azure SDK for .Net
+        - name: Azure SDK for .NET
           href: https://go.microsoft.com/fwlink/?linkid=2092056
         - name: Java Spring provider
           href: https://go.microsoft.com/fwlink/?linkid=2074659