Split Rust test into separate job

.forgejo/workflows/build.yaml

@@ -57,5 +57,14 @@ jobs:
         run: |
           source venv/bin/activate
           pytest tests/*.py
+
+  rust-test:
+    name: Rust test
+    runs-on: ubuntu-22.04
+    steps:
+      - name: Checkout the code
+        uses: actions/checkout@v4
+      - name: Set up Rust
+        uses: https://github.com/dtolnay/rust-toolchain@stable
       - name: Run Rust tests
         run: cargo test