Clarify CI targets in README #371

Job	Run time
lint	39s
cargo-deny (advisories)	18s
cargo-deny (bans licenses sources)	18s
msrv-x86_64-unknown-freebsd / build	2m 25s
aarch64-apple-darwin / build	1m 0s
aarch64-apple-ios / build	1m 5s
aarch64-unknown-linux-gnu / build	46s
arm-linux-androideabi / build	34s
aarch64-unknown-linux-musl / build	1m 14s
armv7-linux-androideabi / build	36s
i686-pc-windows-gnu / build	3m 7s
i686-pc-windows-msvc / build	2m 46s
i686-unknown-linux-musl / build	1m 27s
i686-unknown-linux-gnu / build	41s
msrv-aarch64-apple-darwin / build	2m 25s
msrv-arm-linux-androideabi / build	2m 19s
msrv-x86_64-pc-windows-msvc / build	3m 52s
msrv-x86_64-unknown-linux-gnu / build	2m 25s
msrv-x86_64-unknown-linux-musl / build	2m 36s
msrv-x86_64-unknown-netbsd / build	2m 20s
aarch64-apple-darwin-nightly / build	53s
x86_64-apple-darwin / build	59s
x86_64-pc-windows-gnu / build	2m 51s
x86_64-pc-windows-msvc / build	2m 22s
x86_64-pc-windows-msvc-nightly / build	3m 26s
x86_64-unknown-freebsd / build	23s
x86_64-unknown-linux-gnu / build	1m 10s
x86_64-unknown-linux-gnu-nightly / build	1m 19s
x86_64-unknown-linux-musl / build	48s
x86_64-unknown-netbsd / build	23s
	47m 27s

Provide feedback