Update version to 14.15.0 in Directory.Build.props

The version number in the `Directory.Build.props` file has been updated. Specifically, the `<Version>` element has been changed from `14.15.0-rc.1` to `14.15.0`, indicating that the release candidate version has been updated to the final release version.

src/Directory.Build.props

@@ -5,6 +5,6 @@
     <Copyright>(C) 2024 [email protected]</Copyright>
     <AssemblyVersion>14.15.0</AssemblyVersion>
     <FileVersion>14.15.0</FileVersion>
-    <Version>14.15.0-rc.1</Version>
+    <Version>14.15.0</Version>
   </PropertyGroup>
 </Project>