Update README.md

Author: ajlam

samples/tutorials/c#/README.md

@@ -2,10 +2,10 @@
 
 Pick a platform below to get started:
 * [macOS](https://github.com/Microsoft/sql-server-samples/tree/master/samples/tutorials/c%23/macOS)
-* [RHEL](https://github.com/Microsoft/sql-server-samples/tree/master/samples/tutorials/c%23/rhel)
-* [Ubuntu](https://github.com/Microsoft/sql-server-samples/tree/master/samples/tutorials/c%23/ubuntu)
-* [Windows](https://github.com/Microsoft/sql-server-samples/tree/master/samples/tutorials/c%23/windows)
+* [RHEL](https://github.com/Microsoft/sql-server-samples/tree/master/samples/tutorials/c%23/RHEL)
+* [Ubuntu](https://github.com/Microsoft/sql-server-samples/tree/master/samples/tutorials/c%23/Ubuntu)
+* [Windows](https://github.com/Microsoft/sql-server-samples/tree/master/samples/tutorials/c%23/Windows)
 
 .NET Framework is pre-installed with Windows. For Linux and Mac OS X you can download [.NET Core](https://www.microsoft.com/net/core#windows).
 
-Please visit our [getting started tutorials](https://www.microsoft.com/en-us/sql-server/developer-get-started/)
+Please visit our [getting started tutorials](https://www.microsoft.com/en-us/sql-server/developer-get-started/)