Add the "-Wno-ignored-attributes" for the ignoring attributes on template parameters warning

This is to suppress a bogus warning(and therefore error) on the CI while migrating to Ubuntu 24. See ARM-software/ComputeLibrary#330

Author: aaronj0

CMakeLists.txt

@@ -299,7 +299,7 @@ endif()
 
 # Add appropriate flags for GCC
 if (LLVM_COMPILER_IS_GCC_COMPATIBLE)
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fno-common -Woverloaded-virtual -Wcast-qual -fno-strict-aliasing -pedantic -Wno-long-long -Wall -W -Wno-unused-parameter -Wwrite-strings")
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fno-common -Woverloaded-virtual -Wcast-qual -fno-strict-aliasing -pedantic -Wno-long-long -Wall -W -Wno-unused-parameter -Wwrite-strings -Wno-ignored-attributes")
 endif ()
 
 # Fixes "C++ exception handler used, but unwind semantics are not enabled" warning Windows