ci: Add Github workflows

This patch adds two github workflows that will run on each commit, and
also regularly: CodeQL and govulncheck.

.github/workflows/govulncheck.yml

@@ -0,0 +1,24 @@
+name: "govulncheck"
+
+on:
+  push:
+    branches: [ "master", "next" ]
+  pull_request:
+    # The branches below must be a subset of the branches above
+    branches: [ "master", "next" ]
+  schedule:
+    - cron: '29 21 * * 6'
+
+jobs:
+  govulncheck:
+    runs-on: ubuntu-latest
+    timeout-minutes: 5
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-go@v3
+        with:
+          go-version: ">=1.19.2"
+      - name: install govulncheck
+        run: go install golang.org/x/vuln/cmd/govulncheck@latest
+      - name: run govulncheck
+        run: govulncheck ./...