Fix build

Author: jahn96

package.json

@@ -67,8 +67,7 @@
     "@lumino/messaging": "^1.4.3",
     "@lumino/properties": "^1.2.3",
     "@lumino/signaling": "^1.4.3",
-    "@lumino/widgets": "^1.13.2",
-    "@types/react": "^16.9.56"
+    "@lumino/widgets": "^1.13.2"
   },
   "devDependencies": {
     "@jupyterlab/builder": "^3.0.0-rc.13",
@@ -83,6 +82,7 @@
     "@types/enzyme-adapter-react-16": "^1.0.6",
     "@types/jest": "^26.0.15",
     "@types/node-fetch": "^2.5.7",
+    "@types/react": "^16.9.56",
     "@types/react-dom": "^16.9.9",
     "@types/react-test-renderer": "^16.9.3",
     "babel-jest": "^26.6.3",
@@ -103,6 +103,9 @@
     "react-test-renderer": "^17.0.1",
     "ts-jest": "^26.4.4"
   },
+  "resolutions": {
+    "@types/react": "^16.9.56"
+  },
   "sideEffects": [
     "style/*.css",
     "style/index.js"