Add codeql workflow (#35)

Author: xukaren

.github/workflows/codeql-analysis.yml

@@ -0,0 +1,30 @@
+name: "CodeQL"
+
+on:
+  workflow_dispatch:
+  schedule:
+    - cron: '30 1 * * *'
+
+jobs:
+  CodeQL-Build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v2
+
+      - name: Initialize CodeQL
+        uses: github/codeql-action/init@v1
+        with:
+          languages: java
+
+      - name: Setup Java 11
+        uses: actions/setup-java@v1
+        with:
+          java-version: 11
+
+      - name: Autobuild
+        uses: github/codeql-action/autobuild@v1
+
+      - name: Perform CodeQL Analysis
+        uses: github/codeql-action/analyze@v1