ci: cache the ruleset

.github/workflows/build.yml

@@ -42,6 +42,8 @@ jobs:
         run: python -m pip install --upgrade pip setuptools
       - name: Install capa with build requirements
         run: pip install -e .[build]
+      - name: Cache the rule set
+        run: python ./scripts/cache-ruleset.py ./rules/ ./cache/
       - name: Build standalone executable
         run: pyinstaller --log-level DEBUG .github/pyinstaller/pyinstaller.spec
       - name: Does it run (PE)?