Add a macOS and Windows job to CI matrix

.github/workflows/ci.yml

@@ -8,12 +8,21 @@ on:
 
 jobs:
   install:
-    name: Rust ${{matrix.rust}}
+    name: Rust ${{matrix.rust}} on ${{matrix.name}}
-    runs-on: ubuntu-latest
+    runs-on: ${{matrix.os}}-latest
     strategy:
       fail-fast: false
       matrix:
+        name: [Linux]
+        os: [ubuntu]
         rust: [nightly, beta, stable]
+        include:
+          - name: macOS
+            os: macos
+            rust: nightly
+          - name: Windows
+            os: windows
+            rust: nightly
     steps:
       - uses: actions/checkout@v3
       - uses: ./