Fix CI (dropped Windows accidentally)

Author: cowtowncoder

.github/workflows/main.yml

@@ -21,14 +21,19 @@ permissions:
 
 jobs:
   build:
-    runs-on: 'ubuntu-22.04'
+    # Here we DO need "os" option, to include Windows
+    runs-on: ${{ matrix.os }}
     strategy:
       fail-fast: false
       matrix:
         java_version: ['8', '11', '17', '21', '22']
+        os: ['ubuntu-22.04']
         include:
           - java_version: '8'
+            os: 'ubuntu-22.04'
             release_build: 'R'
+          - java_version: '8'
+            os: 'windows-latest'
             is_windows: 'W'
     env:
       JAVA_OPTS: "-XX:+TieredCompilation -XX:TieredStopAtLevel=1"