ci: add msys workflow

.github/workflows/msys2.yaml

@@ -0,0 +1,26 @@
+name: msys2
+
+on:
+  pull_request:
+  push:
+
+jobs:
+  msys2:
+    runs-on: windows-latest
+    defaults:
+      run:
+        shell: msys2 {0}
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+      - name: Set up msys
+        uses: msys2/setup-msys2@v2
+        with:
+          msystem: MSYS
+          update: true
+          install: mingw-w64-gcc mingw-w64-pkg-config mingw-w64-gtk4 mingw-w64-libadwaita
+      - name: Set up Go
+        uses: actions/setup-go@v4
+      - name: Build
+        run: |
+          go build main.go