CI: Run CI on java16 for all platforms to ensure no illegal access violations occur.

.github/workflows/illegalAccessCheck.yml

@@ -0,0 +1,85 @@
+name: CI
+
+on:
+  push:
+    branches:
+      - 'master'
+  pull_request:
+    branches:
+      - '*'
+jobs:
+  windows:
+    name: Windows (Java 16)
+    runs-on: windows-latest
+    steps:
+      - uses: actions/checkout@v2
+        with:
+          fetch-depth: 2
+      - name: Set up JDK 16
+        uses: actions/setup-java@v1
+        with:
+          java-version: 16
+      - name: Build & Test
+        uses: eskatos/gradle-command-action@v1
+        with:
+          arguments: build test -PskipAutostyle --no-daemon
+          wrapper-cache-enabled: true
+          dependencies-cache-enabled: true
+          configuration-cache-enabled: true
+      - name: Upload Test Results
+        uses: actions/upload-artifact@v1
+        if: ${{ always() }}
+        with:
+          name: windows-test-results
+          path: build/test_results
+
+  linux:
+    name: Linux (Java 16)
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+        with:
+          fetch-depth: 2
+      - name: Set up JDK 16
+        uses: actions/setup-java@v1
+        with:
+          java-version: 16
+      - name: Build & Test
+        env:
+          PROPS_GITHUB: "-PgithubAccessToken=${{ secrets.GITHUB_TOKEN }}"
+        run: xvfb-run -a -server-num=1 --server-args="-screen 0 2000x3000x16" ./gradlew build test -PskipAutostyle  -PfailIfLibraryMissing=true $(echo $PROPS_GITHUB) --no-daemon
+      - name: Upload Test Results
+        if: ${{ always() }}
+        uses: actions/upload-artifact@v1
+        with:
+          name: linux-test-results
+          path: build/test_results
+
+  macos:
+    name: macOS (Java 16)
+    runs-on: macos-latest
+    steps:
+      - uses: actions/checkout@v2
+        with:
+          fetch-depth: 2
+      - name: Set up JDK 16
+        uses: actions/setup-java@v1
+        with:
+          java-version: 16
+      - name: Setup XCode
+        uses: maxim-lobanov/setup-xcode@v1
+        with:
+          xcode-version: '12.1'
+      - name: Build & Test
+        uses: eskatos/gradle-command-action@v1
+        with:
+          arguments: build test -PskipAutostyle --no-daemon
+          wrapper-cache-enabled: true
+          dependencies-cache-enabled: true
+          configuration-cache-enabled: true
+      - name: Upload Test Results
+        uses: actions/upload-artifact@v1
+        if: ${{ always() }}
+        with:
+          name: macOS-test-results
+          path: build/test_results