[CI] Add windows ci

This PR adds windows CI.

.github/workflows/windows-build.yaml

@@ -0,0 +1,39 @@
+# GH actions.
+# We use it to cover windows builds
+# Jenkins is still the primary CI
+name: Windows CI
+
+on:
+  push:
+    branches:
+      - win
+  pull_request:
+    branches:
+      - main
+
+jobs:
+  Windows:
+    runs-on: windows-latest
+    defaults:
+      run:
+        shell: 'cmd /C call {0}'
+
+    steps:
+    - uses: actions/checkout@v3
+      with:
+        submodules: 'recursive'
+
+    - uses: conda-incubator/setup-miniconda@v2
+      with:
+        activate-environment: mlc-llm-build
+        channel-priority: strict
+        environment-file: ci/build-environment.yaml
+        auto-activate-base: false
+    - name: Conda info
+      run: |
+        conda info
+        conda list
+        python --version
+    - name: Build MLC-LLM
+      run: >-
+        ci/task/build_win.bat

ci/build-environment.yaml

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+name: mlc-llm-build
+
+channels:
+  - conda-forge
+
+dependencies:
+  - conda-build
+  - anaconda-client
+  - libvulkan-headers
+  - libvulkan-loader
+  - spirv-tools
+  - spirv-headers
+  - git
+  - cmake
+  - bzip2

ci/task/build_win.bat

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+cd mlc-llm
+rd /s /q build
+mkdir build
+cd build
+
+cmake -A x64 -Thost=x64 ^
+      -G "Visual Studio 17 2022" ^
+      -DUSE_VULKAN=ON ^
+      ..
+
+cmake --build . --parallel 3 --config Release -- /m
+
+cd ..\..
+
+IF %ERRORLEVEL% EQU 0 (
+    echo Build success
+) else (
+    echo Build failed
+    exit /b 1
+)