Update index.md

Author: egil

docs/site/index.md

@@ -47,7 +47,7 @@ bUnit is available on NuGet in various incarnations. If you are using xUnit as y
 
 ## Sponsors
 
-A hugh thank you to the [sponsors of my work with bUnit](https://github.com/sponsors/egil). The higher tire sponsors are:
+A hugh thank you to the [sponsors of my work with bUnit](https://github.com/sponsors/egil). The higher tier sponsors are:
 
 - [Hassan Rezk Habib (@hassanhabib)](https://github.com/hassanhabib)