Add a WASI cross-check to CI.

Author: sunfishcode

.github/workflows/main.yml

@@ -150,6 +150,7 @@ jobs:
         riscv64gc-unknown-linux-gnu
         arm-unknown-linux-gnueabihf
         aarch64-linux-android
+        wasm32-wasi
     - run: cargo check --workspace --all-targets --all-features --release -vv
     - run: cargo check --workspace --all-targets --all-features --release -vv --target=x86_64-unknown-linux-musl
     - run: cargo check --workspace --all-targets --all-features --release -vv --target=x86_64-unknown-linux-gnux32
@@ -163,6 +164,7 @@ jobs:
     - run: cargo check --workspace --all-targets --all-features --release -vv --target=riscv64gc-unknown-linux-gnu
     - run: cargo check --workspace --all-targets --all-features --release -vv --target=arm-unknown-linux-gnueabihf
     - run: cargo check --workspace --all-targets --all-features --release -vv --target=aarch64-linux-android
+    - run: cd cap-std && cargo check --features=fs_utf8 --release -vv
 
   check_cross_nightly_windows:
     name: Check Cross-Compilation on Rust nightly on Windows