changed casing on contributing.md (#9269)

Author: KennyNeal

readme.md

@@ -4,7 +4,7 @@
 
 <img align="left" src=bin/dbatools.png alt="dbatools logo">  dbatools is PowerShell module that you may think of like a command-line SQL Server Management Studio. The project initially started out as just `Start-SqlMigration.ps1`, but as of our 2.0 version release has grown into a collection of [nearly 700 commands](https://dbatools.io/commands) that help automate SQL Server tasks and encourage best practices.
 
-Want to contribute to the project? We'd love to have you! Visit our [contributing.md](contributing.md) for a jump start.
+Want to contribute to the project? We'd love to have you! Visit our [contributing.md](CONTRIBUTING.md) for a jump start.
 
 Want to say thanks? Click the star at the top of the page 🌟