Fix warning

Author: solidpixel

Source/UnitTest/cmake_core.cmake

@@ -66,6 +66,7 @@ target_compile_options(${ASTCENC_TEST}
         $<$<NOT:$<CXX_COMPILER_ID:MSVC>>:-Wno-float-equal>
         $<$<NOT:$<CXX_COMPILER_ID:MSVC>>:-Wno-overriding-option>
         $<$<NOT:$<CXX_COMPILER_ID:MSVC>>:-Wno-unsafe-buffer-usage>
+        $<$<NOT:$<CXX_COMPILER_ID:MSVC>>:-Wno-covered-switch-default>
 
         # Ignore things that the googletest build triggers
         $<$<NOT:$<CXX_COMPILER_ID:MSVC>>:-Wno-unknown-warning-option>