ci: add snyk for devel branch

adding snyk github action to
run weekly on the devel branch.

Signed-off-by: Madhu Rajanna <madhupr007@gmail.com>

.github/workflows/snyk.yaml

@@ -0,0 +1,25 @@
+---
+name: Security scanning
+# yamllint disable-line rule:truthy
+on:
+  schedule:
+    # Run weekly on Monday
+    - cron:  '0 0 * * 1'
+
+permissions:
+  contents: read
+
+jobs:
+  security:
+    if: github.repository == 'ceph/ceph-csi'
+    runs-on: ubuntu-latest
+    steps:
+      - name: checkout
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: run Snyk to check for code vulnerabilities
+        uses: snyk/actions/golang@master
+        env:
+          SNYK_TOKEN: ${{ secrets.SNYK_TOKEN }}