Add CI for building and releasing

.github/workflows/build.yml

@@ -0,0 +1,33 @@
+name: build
+
+on:
+  push:
+    branches:
+      - main
+    tags:
+      - '*'
+  pull_request:
+    types:
+      - opened
+      - reopened
+      - synchronize
+
+jobs:
+  windows:
+    runs-on: windows-2019
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+
+      - name: 'CMake: Configure'
+        run: cmake -B build -A Win32
+
+      - name: 'CMake: Build'
+        run: cmake --build build --config Release
+
+      - name: Release
+        uses: softprops/action-gh-release@v1
+        if: startsWith(github.ref, 'refs/tags/')
+        with:
+          files: build/xiloader/Release/xiloader.exe