Invalid iCCP chunk written

[kornelski]

The chunk is supposed to have named and compressed ICC data: https://www.w3.org/TR/png/#11iCCP

but the encoder seems to just write it raw:

image-png/src/common.rs

Line 769 in 2232f83

encoder::write_chunk(&mut w, chunk::iCCP, iccp)?;

the decoder does parsing and decompression:

image-png/src/decoder/stream.rs

Line 1501 in 2232f83

fn parse_iccp(&mut self) -> Result<Decoded, DecodingError> {

[kornelski]

Fixed in #548