Reduce compression from insane level

Reduced build time by nearly  three minutes and doesn't change the size more than 250kb

       -4, --shrink-insane
              Set the compression level to "insane" using the zopfli compressor.  You can define the compressor iterations with the -i, --iter option.

       -2, --shrink-normal
              Set the compression level to "normal" using the 7z compressor.  This is the default level of compression.