Add GitHub Code Analysis workflow.

Author: bgrainger

.github/workflows/codeql-analysis.yml

@@ -0,0 +1,47 @@
+name: "CodeQL"
+
+on:
+  push:
+    branches: [ master, test ]
+  pull_request:
+    branches: [ master ]
+  schedule:
+    - cron: '31 6 * * 1'
+
+jobs:
+  analyze:
+    name: Analyze
+    runs-on: ubuntu-latest
+    permissions:
+      actions: read
+      contents: read
+      security-events: write
+
+    strategy:
+      fail-fast: false
+      matrix:
+        language: [ 'csharp' ]
+
+    steps:
+    - name: Checkout repository
+      uses: actions/checkout@v2
+
+    - name: Set up .NET 6.0
+      uses: actions/setup-dotnet@v1
+      with:
+        dotnet-version: 6.0.100-preview.5.21302.13
+
+    - 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
+
+    - name: Autobuild
+      uses: github/codeql-action/autobuild@v1
+
+    - name: Perform CodeQL Analysis
+      uses: github/codeql-action/analyze@v1