Add rustup target in CI

Author: Heliozoa

.github/workflows/test.yml

@@ -38,6 +38,8 @@ jobs:
           components: clippy, rustfmt
       - name: Cache
         uses: Swatinem/rust-cache@v2
+      - name: Add rustup target
+        run: rustup target add ${{ matrix.target }}
 
       - name: Diagnostics on Windows
         if: matrix.os == 'windows-latest'