github: build: Specify target in cargo step

Signed-off-by: Patrick José Pereira <patrickelectric@gmail.com>

.github/workflows/build.yml

@@ -93,7 +93,7 @@ jobs:
         with:
           use-cross: true
           command: build
-          args: --release --bin simple-http-server --locked
+          args: --release --bin simple-http-server --locked --target=${{ matrix.TARGET }}
       - uses: actions/upload-artifact@v2
         with:
           name: ${{ matrix.target }}-simple-http-server${{ env.BINARY_EXTENSION }}