Update MSRV and fix clippy issues #1203

Job	Run time
test_features	24s
Fuzz targets (cargo-fuzz)	5m 28s
Fuzz targets (afl)	1m 43s
clippy	2m 4s
test_features (default)	1m 39s
public_private_dependencies	18s
test_features (gif)	52s
test_avif	1m 32s
test_avif_decoding	1m 59s
test_features (jpeg)	27s
test_features (png)	36s
test_other_archs (powerpc-unknown-linux-gnu, default)	4m 8s
test_toolchains (1.63.0)	37s
test_features (tiff)	30s
test_other_archs (powerpc-unknown-linux-gnu, webp-encoder)	2m 10s
build_benchmarks	41s
test_toolchains (nightly)	1m 37s
test_features (ico)	47s
test_other_archs (i686-unknown-linux-gnu, default)	1m 40s
test_toolchains (beta)	1m 37s
test_features (pnm)	26s
test_other_archs (i686-unknown-linux-gnu, webp-encoder)	55s
cargo-deny	21s
test_features (tga)	25s
test_features (webp)	24s
rustfmt	17s
verify_msrv	3m 29s
test_features (bmp)	26s
test_features (hdr)	22s
test_features (dxt)	26s
test_features (dds)	29s
test_features (farbfeld)	21s
test_features (openexr)	45s
test_features (jpeg_rayon)	35s
test_features (webp-encoder)	58s
	41m 28s

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