Add Github Code Scanning (#11211)

Github just released Github Code Scanning:
https://github.blog/2020-09-30-code-scanning-is-now-available/

.github/workflows/codeql-analysis.yml

@@ -0,0 +1,53 @@
+---
+name: "CodeQL"
+
+on:
+  push:
+    branches: [master]
+  pull_request:
+    branches: [master]
+  schedule:
+    - cron: '0 2 * * *'
+
+jobs:
+  analyze:
+    name: Analyze
+    runs-on: ubuntu-latest
+
+    strategy:
+      fail-fast: false
+      matrix:
+        # Override automatic language detection by changing the below list
+        # Supported options are ['csharp', 'cpp', 'go', 'java', 'javascript', 'python']
+        language: ['python', 'javascript']
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v2
+        with:
+          # We must fetch at least the immediate parents so that if this is
+          # a pull request then we can checkout the head.
+          fetch-depth: 2
+
+      # If this run was triggered by a pull request event, then checkout
+      # the head of the pull request instead of the merge commit.
+      - run: git checkout HEAD^2
+        if: ${{ github.event_name == 'pull_request' }}
+
+      # Initializes the CodeQL tools for scanning.
+      - name: Initialize CodeQL
+        uses: github/codeql-action/init@v1
+        with:
+          languages: ${{ matrix.language }}
+          # If you wish to specify custom queries, you can do so here or in a config file.
+          # By default, queries listed here will override any specified in a config file.
+          # Prefix the list here with "+" to use these queries and those in the config file.
+          # queries: ./path/to/local/query, your-org/your-repo/queries@main
+
+      # Autobuild attempts to build any compiled languages  (C/C++, C#, or Java).
+      # If this step fails, then you should remove it and run the build manually (see below)
+      - name: Autobuild
+        uses: github/codeql-action/autobuild@v1
+
+      - name: Perform CodeQL Analysis
+        uses: github/codeql-action/analyze@v1