Update Getting-started.md

Author: rockfordlhotka

docs/Getting-started.md

@@ -6,7 +6,7 @@
 
 * Read [What is CSLA](What-is-CSLA-.NET.md)?
 * Get the framework binaries from [NuGet](http://nuget.org/packages?q=csla) or from the [releases page](https://github.com/MarimerLLC/csla/releases).
-* Review the [CSLA Fast Start](https://github.com/MarimerLLC/csla/tree/master/Samples/CslaFastStart) sample.
+* Review the [CSLA Fast Start](https://github.com/MarimerLLC/csla/tree/main/Samples/CslaFastStart) sample.
 
 ## CSLA 10