Add UmbracoCmsPackageVersion property to manage global CMS dependency version

Author: ronaldbarendse

Directory.Packages.props

@@ -9,8 +9,11 @@
     <GlobalPackageReference Include="Umbraco.Code" Version="2.0.0" />
     <GlobalPackageReference Include="Umbraco.GitVersioning.Extensions" Version="0.2.0" />
   </ItemGroup>
+  <PropertyGroup>
+    <UmbracoCmsPackageVersion>[12.0.0, 13)</UmbracoCmsPackageVersion>
+  </PropertyGroup>
   <ItemGroup>
-    <PackageVersion Include="Umbraco.StorageProviders.AzureBlob" Version="[12.0.0, 13)" />
-    <PackageVersion Include="Umbraco.StorageProviders.AzureBlob.ImageSharp" Version="[12.0.0, 13)" />
+    <PackageVersion Include="Umbraco.StorageProviders.AzureBlob" Version="$(UmbracoCmsPackageVersion)" />
+    <PackageVersion Include="Umbraco.StorageProviders.AzureBlob.ImageSharp" Version="$(UmbracoCmsPackageVersion)" />
   </ItemGroup>
 </Project>