Add `--ignore-unknown-features` to the CI. #689

Job	Run time
cargo check (msrv) (wasm32)	25s
cargo check (msrv) (windows-latest)	49s
cargo clippy (windows-latest)	1m 23s
cargo clippy (wasm32)	42s
cargo check (msrv) (macos-latest)	29s
cargo clippy (macos-latest)	38s
cargo check (msrv) (ubuntu-latest)	22s
cargo clippy (ubuntu-latest)	43s
cargo doc	21s
cargo fmt	23s
cargo test (wasm32)	18s
cargo test (windows-latest)	1m 4s
typos	6s
cargo test (macos-latest)	23s
cargo test (ubuntu-latest)	18s
	8m 24s

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