Add back CodeQL

.github/workflows/codeql-analysis.yml

@@ -0,0 +1,30 @@
+name: "CodeQL"
+on:
+  push:
+    paths:
+      - "src/Picocrypt.go"
+  pull_request:
+    branches: [ main ]
+jobs:
+  analyze:
+    name: Analyze
+    runs-on: ubuntu-latest
+    permissions:
+      actions: read
+      contents: read
+      security-events: write
+    strategy:
+      fail-fast: false
+      matrix:
+        language: ['go']
+    steps:
+    - name: Checkout Repository
+      uses: actions/checkout@v2
+    - name: Initialize CodeQL
+      uses: github/codeql-action/init@v1
+      with:
+        languages: ${{ matrix.language }}
+    - name: Autobuild
+      uses: github/codeql-action/autobuild@v1
+    - name: Perform CodeQL Analysis
+      uses: github/codeql-action/analyze@v1