Temporarily disable PCX format #1702

Job	Run time
test_avif_decoding	1m 52s
test_features	25s
clippy	2m 25s
test_features (default)	1m 47s
Fuzz targets (afl)	2m 36s
test_other_archs (powerpc-unknown-linux-gnu)	2m 57s
test_features (rayon)	33s
test_other_archs (i686-unknown-linux-gnu)	1m 52s
test_features (avif)	1m 0s
test_toolchains (1.70.0)	33s
test_features (bmp)	26s
test_toolchains (nightly)	1m 42s
test_features (dds)	27s
build_benchmarks	46s
test_toolchains (beta)	1m 39s
test_features (exr)	42s
test_features (ff)	30s
test_features (gif)	21s
Fuzz targets (cargo-fuzz)	56s
test_features (hdr)	17s
cargo-deny	20s
test_features (ico)	38s
public_private_dependencies	24s
test_features (jpeg)	30s
rustfmt	14s
test_features (pcx)	17s
test_features (png)	35s
cargo-semver-checks	40s
test_features (pnm)	29s
test_features (qoi)	28s
test_features (tga)	28s
test_features (tiff)	36s
test_features (webp)	27s
	29m 52s

Provide feedback