chore: make the tests run on multiple things

.github/workflows/test.yml

@@ -2,13 +2,20 @@ on: push
 
 jobs:
   test:
-    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        os: [ubuntu-latest, windows-latest]
+        toolchain: [stable, nightly]
+
+    runs-on: ${{ matrix.os }}
     steps:
       - name: Check out code
         uses: actions/checkout@v2
 
       - name: Set up rust
         uses: dtolnay/rust-toolchain@stable
+        with:
+          toolchain: ${{ matrix.toolchain }}
 
       - name: Cache dependencies
         uses: Swatinem/rust-cache@v2