Remove unused/outdated deps. Set default-features = false for serde_with #73

Job	Run time
docs	30s
cfg-check	21s
clippy	27s
doctest	45s
feature-checks	59s
fmt	11s
no-std	22s
test ubuntu-latest stable --no-default-features	19s
wasm-unknown	20s
wasm-wasi	18s
test ubuntu-latest stable	24s
test ubuntu-latest stable --all-features	31s
test ubuntu-latest nightly --no-default-features	29s
test ubuntu-latest nightly	27s
test ubuntu-latest nightly --all-features	35s
test ubuntu-latest 1.79 --no-default-features	26s
test ubuntu-latest 1.79	24s
test windows-latest stable --no-default-features	1m 4s
test windows-latest stable	1m 7s
test windows-latest stable --all-features	1m 20s
test windows-latest nightly --no-default-features	52s
test windows-latest nightly	57s
test windows-latest nightly --all-features	1m 38s
test windows-latest 1.79 --no-default-features	56s
test windows-latest 1.79	1m 36s
	17m 18s

Provide feedback