try windows latest (#298)

Author: Byron

.github/workflows/ci.yml

@@ -40,7 +40,7 @@ jobs:
           - target: x86_64-pc-windows-msvc
             rust: stable-msvc
     name: Windows
-    runs-on: windows-2019
+    runs-on: windows-latest
     steps:
       - uses: actions/checkout@v1
       - uses: actions-rs/toolchain@v1