Bump SIMDE commit to the most up-to-date (1c68d9a)

Signed-off-by: Luis Pereira <lpereira@allbesmart.pt>

cmake_targets/tools/build_helper

@@ -494,8 +494,8 @@ install_simde_from_source(){
     if [[ -v SIMDE_VERSION ]]; then
       git checkout -f $SIMDE_VERSION
     else
-      # At time of writing, last working commit for OAI: c7f26b7
-      git checkout c7f26b73ba8e874b95c2cec2b497826ad2188f68
+      # At time of writing, last working commit for OAI: 1c68d9a
+      git checkout 1c68d9ad60bf63f3fb527c4ee3b2319d828ffcc6
     fi
     # Showing which version is used
     git log -n1