Merge #3092

3092: ci: add a scheduled audit workflow r=quake,liya2017 a=yangby-cryptape

### What problem does this PR solve?

At present, CKB only checks security vulnerabilities when some one submits a pull request.

If no one submit a pull request, we couldn't know whether CKB has security vulnerabilities or not.

This PR add a scheduled audit workflow to check security vulnerabilities daily.
So we could know any security vulnerability in 24 hours after it became public.

Ref: https://github.com/actions-rs/audit-check#scheduled-audit

### Check List

Tests

- No code (skip ci)

### Release note

```release-note
None: Exclude this PR from the release note.
```



Co-authored-by: Boyu Yang <[email protected]>

.github/workflows/scheduled_audit.yaml

@@ -0,0 +1,12 @@
+name: Security Audit
+on:
+  schedule:
+    - cron: '0 0 * * *'
+jobs:
+  audit:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v1
+      - uses: yangby-cryptape/cargo-audit-check-action@customized-for-ckb
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}