Update pr-test-rust.yml to add a "finish" step (#1975)

.github/workflows/pr-test-rust.yml

@@ -26,14 +26,23 @@ jobs:
       - name: Install dependencies
         run: |
           bash scripts/ci_install_rust.sh
+
       - name: Run fmt
         run: |
           source "$HOME/.cargo/env"
           cd rust/
           cargo fmt -- --check
+
       - name: Run test
         timeout-minutes: 20
         run: |
           source "$HOME/.cargo/env"
           cd rust/
           cargo test
+
+  finish:
+    needs: [unit-test-rust]
+    runs-on: ubuntu-latest
+    steps:
+      - name: Finish
+        run: echo "This is an empty step to ensure that all jobs are completed."