ci: add windows-latest

relates to #42

Author: chenrui333

.github/workflows/main.yml

@@ -9,7 +9,7 @@ jobs:
   test:
     strategy:
       matrix:
-        os: [ubuntu-latest, macOS-latest]
+        os: [ubuntu-latest, macOS-latest, windows-latest]
     runs-on: ${{ matrix.os }}
     steps:
     - uses: actions/checkout@v2