[ci] Fix GitHub actions matrix

Author: dacap

.github/workflows/build.yml

@@ -6,7 +6,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [windows-2019, macos-latest, ubuntu-latest]
+        os: [windows-latest, macos-latest, ubuntu-latest]
         build_type: [debug,release]
         benchmark: [false]
         sanitizer: [""]