Use --group-features arbitrary,bytemuck,serde,subtle,zeroize

Groups the optional dependencies in `test` step to improve test times.

We test they all build independently of one another in the `build` step.

Author: tarcieri

.github/workflows/hybrid-array.yml

@@ -105,5 +105,5 @@ jobs:
         with:
           toolchain: ${{ matrix.toolchain }}
       - uses: RustCrypto/actions/cargo-hack-install@master
-      - run: cargo hack test --feature-powerset --optional-deps arbitrary,bytemuck,serde,subtle,zeroize
+      - run: cargo hack test --feature-powerset --optional-deps arbitrary,bytemuck,serde,subtle,zeroize --group-features arbitrary,bytemuck,serde,subtle,zeroize
       - run: cargo test --all-features --release