ci: make benchmark a separate job

.github/workflows/tests.yml

@@ -18,6 +18,17 @@ jobs:
         uses: pypa/hatch@install
       - name: Run tests
         run: hatch test
+
+  benchmark:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.10"
+      - name: Install Hatch
+        uses: pypa/hatch@install
       - name: Run benchmarks
         run: |
           hatch run bench:all