ci: add CodeQL scans and badges

.github/workflows/codeql.yml

@@ -0,0 +1,36 @@
+name: "CodeQL"
+
+on:
+  push:
+    branches: ["main"]
+  pull_request:
+    # The branches below must be a subset of the branches above
+    branches: ["main"]
+  schedule:
+    - cron: "47 23 * * 5"
+
+jobs:
+  analyze:
+    name: Analyze
+    runs-on: ubuntu-latest
+    permissions:
+      actions: read
+      contents: read
+      security-events: write
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Initialize CodeQL
+        uses: github/codeql-action/init@v3
+        with:
+          languages: go
+
+      - name: Autobuild
+        uses: github/codeql-action/autobuild@v3
+
+      - name: Perform CodeQL Analysis
+        uses: github/codeql-action/analyze@v3
+        with:
+          category: "/language:go"

README.md

@@ -1,3 +1,6 @@
+[![CodeQL](https://github.com/isometry/terraform-provider-deepmerge/actions/workflows/codeql.yml/badge.svg)](https://github.com/isometry/terraform-provider-deepmerge/actions/workflows/codeql.yml)
+[![Go Report Card](https://goreportcard.com/badge/github.com/isometry/terraform-provider-deepmerge)](https://goreportcard.com/report/github.com/isometry/terraform-provider-deepmerge)
+
 # Terraform Provider Deepmerge
 
 Deepmerge functions for Terraform 1.8+.