Bump `serdect` to v0.3.0-rc.0 (#1084) #2116

Job	Run time
build (1.73.0, thumbv7em-none-eabi)	43s
cross (armv7-unknown-linux-gnueabihf, 1.73.0)	1m 37s
build (1.73.0, wasm32-unknown-unknown)	39s
doc	54s
cross (armv7-unknown-linux-gnueabihf, stable)	1m 20s
test (i686-unknown-linux-gnu, 1.73.0, sudo apt update && sudo apt install gcc-multilib)	1m 57s
build (stable, thumbv7em-none-eabi)	36s
cross (aarch64-unknown-linux-gnu, 1.73.0)	1m 22s
test (i686-unknown-linux-gnu, stable, sudo apt update && sudo apt install gcc-multilib)	1m 58s
cross (aarch64-unknown-linux-gnu, stable)	1m 19s
build (stable, wasm32-unknown-unknown)	33s
test (x86_64-unknown-linux-gnu, 1.73.0)	1m 30s
cross (powerpc-unknown-linux-gnu, 1.73.0)	1m 30s
test (x86_64-unknown-linux-gnu, stable)	1m 18s
cross (powerpc-unknown-linux-gnu, stable)	1m 24s
	18m 40s

Provide feedback