Added CodeQL. (#5)

.github/codeql/codeql-config.yml

@@ -0,0 +1,6 @@
+name: "CodeQL Config"
+
+queries:
+  - uses: security-and-quality
+paths:
+  - dist

.github/workflows/codeql-analysis.yml

@@ -0,0 +1,41 @@
+name: "CodeQL"
+
+on:
+  push:
+    branches: [typescript]
+  pull_request:
+    branches: [typescript]
+  schedule:
+    - cron: '0 5 * * 1'
+
+jobs:
+  analyze:
+    name: Analyze
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: Checkout repository
+      uses: actions/checkout@v2
+      with:
+        fetch-depth: 2
+
+    - run: git checkout HEAD^2
+      if: ${{ github.event_name == 'pull_request' }}
+
+    - name: Setup Node.JS
+      uses: actions/setup-node@v2-beta
+      with:
+        node-version: '12'
+    - run: npm ci
+
+    - name: Build codebase
+      run: npm run build
+
+    - name: Initialize CodeQL
+      uses: github/codeql-action/init@v1
+      with:
+        config-file: ./.github/codeql/codeql-config.yml
+        languages: javascript
+
+    - name: Perform CodeQL Analysis
+      uses: github/codeql-action/analyze@v1