Run CI on Windows in addition to Ubuntu (#277)

Co-authored-by: James Hamilton <mrjameshamilton@gmail.com>

.github/workflows/continuous_integration.yml

@@ -8,7 +8,10 @@ on:
       - master
 jobs:
   build:
-    runs-on: ubuntu-latest
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-latest, windows-latest]
     steps:
       - uses: actions/checkout@v2
         with:
@@ -20,4 +23,9 @@ jobs:
         with:
           build-root-directory: proguard-main/
           wrapper-directory: proguard-main/
-          arguments: test :base:testAllJavaVersions :base:jacocoTestReport jar
+          arguments: test :base:testAllJavaVersions :base:jacocoTestReport jar --info
+      - name: Publish Test Report
+        uses: mikepenz/action-junit-report@v3
+        if: always() # always run even if the previous step fails
+        with:
+          report_paths: '**/build/test-results/test/TEST-*.xml'