ci: run fast tests before the full suite

.github/workflows/tests.yml

@@ -95,6 +95,10 @@ jobs:
       run: sudo apt-get install -y libyaml-dev
     - name: Install capa
       run: pip install -e .[dev]
+    - name: Run tests (fast)
+      # this set of tests runs about 80% of the cases in 20% of the time,
+      # and should catch most errors quickly.
+      run:  pre-commit run pytest-fast --all-files
     - name: Run tests
       run: pytest -v tests/