Add CodeQL scanning

Author: jnyrup

.github/workflows/codeql.yml

@@ -0,0 +1,50 @@
+name: "CodeQL"
+
+on:
+  push:
+    branches: [ "develop", "master" ]
+  pull_request:
+    branches: [ "develop", "master" ]
+  schedule:
+    - cron: '00 15 * * 1'
+
+jobs:
+  analyze:
+    name: Analyze
+    runs-on: 'ubuntu-latest'
+    timeout-minutes: 360
+    permissions:
+      actions: read
+      contents: read
+      security-events: write
+
+    strategy:
+      fail-fast: false
+      matrix:
+        language: [ 'csharp' ]
+
+    steps:
+    - name: Checkout repository
+      uses: actions/checkout@v4
+
+    # Initializes the CodeQL tools for scanning.
+    - name: Initialize CodeQL
+      uses: github/codeql-action/init@v3
+      with:
+        languages: ${{ matrix.language }}
+        # If you wish to specify custom queries, you can do so here or in a config file.
+        # By default, queries listed here will override any specified in a config file.
+        # Prefix the list here with "+" to use these queries and those in the config file.
+
+        # For more details on CodeQL's query packs, refer to: https://docs.github.com/en/code-security/code-scanning/automatically-scanning-your-code-for-vulnerabilities-and-errors/configuring-code-scanning#using-queries-in-ql-packs
+        # queries: security-extended,security-and-quality
+
+    - name: Build
+      run: |
+        dotnet restore FluentAssertions.sln --configfile nuget.config
+        dotnet build FluentAssertions.sln --configuration CI --no-restore
+
+    - name: Perform CodeQL Analysis
+      uses: github/codeql-action/analyze@v3
+      with:
+        category: "/language:${{matrix.language}}"