Fix typo in building.md

BUILDING.md

@@ -28,7 +28,7 @@ The build.cake script contains a number of interdependent tasks. The most
 important top-level tasks to use are listed here:
 
 ```
- FetchPackages           Retrieves the latest versions of the required assemblies, from the lates NuGet packages.
+ FetchPackages           Retrieves the latest versions of the required assemblies, from the latest NuGet packages.
  CreateImage             Extracts the assemblies from the NuGet packages, and adds other required files to an image directory.
  PackageMsi              Builds the MSI.
 ```