clean before build

Author: sebastianbenz

.github/workflows/CI.yml

@@ -21,6 +21,7 @@ jobs:
           node-version: ${{ matrix.node }}
           registry-url: https://registry.npmjs.org
       - name: install
+        run: npx lerna clean --yes
         run: npx lerna bootstrap --hoist
       - name: test
         run: npm test