[880] deduplicate

Author: bollwyvl

package.json

@@ -47,7 +47,8 @@
     "verdaccio": "file:packages/_not-a-package"
   },
   "scripts": {
-    "bootstrap": "jlpm --no-optional --prefer-offline && lerna bootstrap && jlpm clean && jlpm build && jlpm lint",
+    "bootstrap": "jlpm --no-optional --prefer-offline && jlpm deduplicate && lerna bootstrap && jlpm clean && jlpm build && jlpm lint",
+    "deduplicate": "yarn-deduplicate -s fewer --fail",
     "build": "jlpm build:schema && jlpm build:meta && jlpm build:ws && jlpm build:labextension",
     "build:schema": "lerna run build:schema --stream",
     "build:meta": "lerna run build --stream --scope @jupyter-lsp/jupyterlab-lsp-metapackage",