CI: Run "govulncheck".

.github/workflows/govuln.yml

@@ -0,0 +1,47 @@
+name: Go Vulnerability Checker
+on:
+  push:
+    branches: [ master ]
+    paths:
+      - '.github/workflows/govuln.yml'
+      - '**.go'
+      - 'go.*'
+  pull_request:
+    branches: [ master ]
+    paths:
+      - '.github/workflows/govuln.yml'
+      - '**.go'
+      - 'go.*'
+  schedule:
+    - cron: "0 2 * * SUN"
+
+permissions:
+  contents: read
+
+jobs:
+  run:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        go-version:
+          - "1.20"
+          - "1.21"
+          - "1.22"
+    steps:
+    - uses: actions/checkout@v4
+    - uses: actions/setup-go@v5
+      with:
+        go-version: ${{ matrix.go-version }}
+
+    - run: date
+
+    - name: Install dependencies
+      run: |
+        sudo apt -y update && sudo apt -y install protobuf-compiler
+        make common
+
+    - name: Install and run govulncheck
+      run: |
+        set -euo pipefail
+        go install golang.org/x/vuln/cmd/govulncheck@latest
+        govulncheck ./...