chore: enable optional chaining and nullish (#306)

package.json

@@ -13,6 +13,8 @@
   "homepage": "https://verdaccio.org",
   "main": "index.js",
   "devDependencies": {
+    "@babel/plugin-proposal-nullish-coalescing-operator": "7.7.4",
+    "@babel/plugin-proposal-optional-chaining": "7.7.4",
     "@commitlint/cli": "8.2.0",
     "@commitlint/config-conventional": "8.2.0",
     "@emotion/core": "10.0.22",
@@ -35,10 +37,10 @@
     "@types/validator": "12.0.0",
     "@types/webpack-env": "1.14.1",
     "@typescript-eslint/parser": "2.8.0",
-    "@verdaccio/babel-preset": "8.2.0",
-    "@verdaccio/commons-api": "8.3.0",
-    "@verdaccio/eslint-config": "8.2.0",
-    "@verdaccio/types": "8.3.0",
+    "@verdaccio/babel-preset": "8.4.2",
+    "@verdaccio/commons-api": "8.4.2",
+    "@verdaccio/eslint-config": "8.4.2",
+    "@verdaccio/types": "8.4.2",
     "autosuggest-highlight": "3.1.1",
     "babel-loader": "8.0.6",
     "bundlesize": "0.18.0",
@@ -54,14 +56,14 @@
     "enzyme": "3.10.0",
     "enzyme-adapter-react-16": "1.15.1",
     "enzyme-to-json": "3.4.3",
-    "eslint": "6.6.0",
+    "eslint": "6.7.0",
     "eslint-plugin-codeceptjs": "1.2.0",
     "eslint-plugin-import": "2.18.2",
     "eslint-plugin-jsx-a11y": "6.2.3",
     "eslint-plugin-prettier": "3.1.1",
     "eslint-plugin-react": "7.16.0",
     "eslint-plugin-react-hooks": "2.3.0",
-    "eslint-plugin-verdaccio": "8.2.0",
+    "eslint-plugin-verdaccio": "8.4.2",
     "file-loader": "4.3.0",
     "friendly-errors-webpack-plugin": "1.7.0",
     "get-stdin": "7.0.0",
@@ -113,8 +115,8 @@
     "url-loader": "2.3.0",
     "validator": "12.1.0",
     "verdaccio": "4.3.5",
-    "verdaccio-auth-memory": "8.3.0",
-    "verdaccio-memory": "8.3.0",
+    "verdaccio-auth-memory": "8.4.2",
+    "verdaccio-memory": "8.4.2",
     "wait-on": "3.3.0",
     "webpack": "4.41.2",
     "webpack-bundle-analyzer": "3.6.0",