chore(ci): codeql scans and security policy

Signed-off-by: Carlos A Becker <caarlos0@gmail.com>

.github/workflows/codeql.yml

@@ -0,0 +1,21 @@
+name: "codeql"
+
+on:
+  push:
+    branches: [ main ]
+
+jobs:
+  analyze:
+    name: analyze
+    runs-on: ubuntu-latest
+
+    permissions:
+      security-events: write
+      actions: read
+      contents: read
+
+    steps:
+    - uses: actions/checkout@v2
+    - uses: github/codeql-action/init@v1
+    - uses: github/codeql-action/autobuild@v1
+    - uses: github/codeql-action/analyze@v1

SECURITY.md

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+# Security Policy
+
+## Supported Versions
+
+Only the last stable version at any given point.
+
+## Reporting a Vulnerability
+
+Vulnerabilies can be disclosed via email to carlos@becker.software