Add engines in package.json (#3201)

* Update package.json

* Update package.json

* Update package.json

* Update package.json

package.json

@@ -94,5 +94,8 @@
     "hooks": {
       "pre-commit": "yarn flow && lint-staged"
     }
+  },
+  "engines": {
+    "node": ">=8"
   }
 }

packages/benchmarks/package.json

@@ -38,5 +38,8 @@
     "webpack-bundle-analyzer": "^3.3.2",
     "webpack-cli": "^3.3.3"
   },
-  "sideEffects": false
+  "sideEffects": false,
+  "engines": {
+    "node": ">=8"
+  }
 }

packages/sandbox/package.json

@@ -27,5 +27,8 @@
     "react-dom": "^16.8.6",
     "react-is": "^16.8.6",
     "react-live": "^1.11.0"
+  },
+  "engines": {
+    "node": ">=8"
   }
 }

packages/styled-components/package.json

@@ -114,5 +114,8 @@
   "funding": {
     "type": "opencollective",
     "url": "https://opencollective.com/styled-components"
+  },
+  "engines": {
+    "node": ">=8"
   }
 }