ci: add codeql analysis

.github/workflows/ci.yml

@@ -2,6 +2,9 @@ name: ci
 
 on:
   push:
+    branches: [master]
+  pull_request:
+    branches: [master]
   schedule:
   - cron: '7 4 * * 4'  # weekly on thursday morning
 
@@ -54,3 +57,30 @@ jobs:
         kubectl cluster-info
         kubectl proxy &
         make e2e-with-kind
+
+  codeql:
+    runs-on: ubuntu-latest
+    steps:
+    - 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: python
+        # 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: Perform CodeQL Analysis
+      uses: github/codeql-action/analyze@v1