ci: add temporary VPS fingerprint helper

.github/workflows/vps-host-fingerprint.yml

@@ -0,0 +1,18 @@
+name: VPS Host Fingerprint
+
+on:
+  workflow_dispatch:
+
+jobs:
+  fingerprint:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Read VPS RSA host fingerprint
+        uses: appleboy/ssh-action@v1.2.2
+        with:
+          host: ${{ secrets.VPS_HOST }}
+          username: root
+          key: ${{ secrets.VPS_SSH_KEY }}
+          script: |
+            set -e
+            ssh-keygen -lf /etc/ssh/ssh_host_rsa_key.pub -E sha256 | awk '{print $2}'