f Add CI job running basic VSS tests

Wait for the VSS server and use `checkout@v4`

Poll the server before running tests so the workflow does not race the
startup path, and align the new job with the repository's current
`actions/checkout` version.

Co-Authored-By: HAL 9000

Author: tnull

.github/workflows/vss-tests.yml

@@ -27,19 +27,20 @@ jobs:
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           path: rust-lightning
       - name: Checkout VSS
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           repository: lightningdevkit/vss-server
           path: vss-server
 
       - name: Build and Deploy VSS Server
         run: |
           cd vss-server/rust
-          cargo run server/vss-server-config.toml&
+          cargo run server/vss-server-config.toml > /tmp/vss-server.log 2>&1 &
+          until curl -sf http://localhost:8080/vss > /dev/null; do sleep 1; done
       - name: Run VSS tests
         run: |
           ls -la