fix(ci): 🐛 Fixed type error

Author: zhangxuan2011

.github/workflows/build-toolchain.yml

@@ -91,7 +91,7 @@ jobs:
           set GITHUB_ACTIONS=
 
           :: Build & install in dist/rust9x
-          python x.py install --config bootstrap.rust9x.toml --set build.host=${{ matrix.target }} --stage 2
+          python x.py install --config bootstrap.rust9x.toml --set build.host='["${{ matrix.target }}"]' --stage 2
           if %errorlevel% neq 0 exit /b 1
 
       - name: Pack toolchain