ssh-derive: update `syn` and `quote`; MSRV 1.61 #397

Job	Run time
no_std (1.60.0, thumbv7em-none-eabi)	2m 8s
no_std (1.60.0, wasm32-unknown-unknown)	2m 2s
test (1.60.0)	2m 14s
no_std (stable, thumbv7em-none-eabi)	14s
test (stable)	31s
no_std (stable, wasm32-unknown-unknown)	17s
minimal-versions / minimal-versions	48s
	8m 14s

Provide feedback