revert to java 14.0.2 on windows due to https://bugs.openjdk.java.net/browse/JDK-8254920

.github/workflows/package.yaml

@@ -12,10 +12,16 @@ jobs:
       - uses: actions/checkout@v2
         with:
           submodules: true
-      - name: Set up JDK 15.0.1
+      - name: Set up JDK 15.0.2
+        if: ${{ runner.os == 'Linux' }}
         uses: joschi/setup-jdk@v2
         with:
           java-version: 15
+      - name: Set up JDK 14.0.2
+        if: ${{ runner.os == 'Windows' }}
+        uses: actions/setup-java@v1
+        with:
+          java-version: 14.0.2
       - name: Show Build Versions
         run: ./gradlew -v
       - name: Cache Gradle packages