Add workflow for CodeQL analysis action

.github/workflows/codeql-analysis.yml

@@ -0,0 +1,31 @@
+name: "CodeQL"
+
+on:
+  push:
+    branches: [master, develop]
+  pull_request:
+    branches: [master]
+  schedule:
+    - cron: '0 19 * * 1,3,5'
+
+jobs:
+  analyse:
+    name: Analyse
+    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: Initialize CodeQL
+      uses: github/codeql-action/init@v1
+      with:
+        languages: go
+
+    - name: Perform CodeQL Analysis
+      uses: github/codeql-action/analyze@v1

README.md

@@ -2,6 +2,7 @@
 
 <p align="center">
   <a href="https://travis-ci.com/essentialkaos/mdtoc"><img src="https://travis-ci.com/essentialkaos/mdtoc.svg"></a>
+  <a href="https://github.com/essentialkaos/mdtoc/actions?query=workflow%3ACodeQL"><img src="https://github.com/essentialkaos/mdtoc/workflows/CodeQL/badge.svg" /></a>
   <a href="https://goreportcard.com/report/github.com/essentialkaos/mdtoc"><img src="https://goreportcard.com/badge/github.com/essentialkaos/mdtoc"></a>
   <a href="https://codebeat.co/projects/github-com-essentialkaos-mdtoc-master"><img alt="codebeat badge" src="https://codebeat.co/badges/196d721e-00ad-4dff-9032-9b5bbd11b723" /></a>
   <a href="https://essentialkaos.com/ekol"><img src="https://gh.kaos.st/ekol.svg"></a>