Change link to renamed Markdown file

As I've renamed the Markdown file 'Best-Practices/Language-Interop-and-.Net.md' to 'Best-Practices/Language-Interop-and-.NET.md' because the correct casing is '.NET', also renaming the link to this file.

Author: richy58729

README.md

@@ -43,7 +43,7 @@ The guidelines are divided into these sections:
   * [Error Handling](Best-Practices/Error-Handling.md)
   * [Performance](Best-Practices/Performance.md)
   * [Security](Best-Practices/Security.md)
-  * [Language, Interop and .Net](Best-Practices/Language-Interop-and-.Net.md)
+  * [Language, Interop and .Net](Best-Practices/Language-Interop-and-.NET.md)
   * [Metadata, Versioning, and Packaging](Best-Practices/Metadata-Versioning-and-Packaging.md)
 
 ### Current State: