build(cmake): set cmp0135 cmake policy to new

Set the `CMP0135` CMake policy to `NEW`: the timestamps of the
extracted files will reflect the timestamps at extraction.

Setting the `download_extract_timestamp` to `true` (commit 5ca66d6) did
not fix the warning.

CMakeLists.txt

@@ -3,10 +3,8 @@ project(WebAssemblyInterface)
 
 set(CMAKE_CXX_STANDARD 17)
 
-if(${CMAKE_VERSION} VERSION_LESS 3.24)
-  set(download_extract_timestamp_flag)
-else()
-  set(download_extract_timestamp_flag DOWNLOAD_EXTRACT_TIMESTAMP TRUE)
+if(POLICY CMP0135)
+  cmake_policy(SET CMP0135 NEW)
 endif()
 
 set(WebAssemblyInterface_LIBRARIES WebAssemblyInterface)