chore(deps): bump Umbraco.Cms from 12.0.0 to 12.3.4 in /src/TestSite.12

Bumps [Umbraco.Cms](https://github.com/umbraco/Umbraco-CMS) from 12.0.0 to 12.3.4.
- [Release notes](https://github.com/umbraco/Umbraco-CMS/releases)
- [Commits](umbraco/Umbraco-CMS@release-12.0.0...release-12.3.4)

---
updated-dependencies:
- dependency-name: Umbraco.Cms
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

src/TestSite.12/TestSite.12.csproj

@@ -7,7 +7,7 @@
     </PropertyGroup>
 
     <ItemGroup>
-        <PackageReference Include="Umbraco.Cms" Version="12.0.0"/>
+        <PackageReference Include="Umbraco.Cms" Version="12.3.4"/>
         <PackageReference Include="uSync" Version="12.2.3"/>
     </ItemGroup>