build($core): bump webpack-chain version

Author: meteorlxy

packages/@vuepress/core/package.json

@@ -62,7 +62,7 @@
     "vuepress-html-webpack-plugin": "^3.2.0",
     "vuepress-plugin-container": "^2.0.2",
     "webpack": "^4.8.1",
-    "webpack-chain": "^4.6.0",
+    "webpack-chain": "^6.0.0",
     "webpack-dev-server": "^3.5.1",
     "webpack-merge": "^4.1.2",
     "webpackbar": "3.2.0"

yarn.lock

@@ -7184,6 +7184,11 @@ javascript-stringify@^1.6.0:
   version "1.6.0"
   resolved "https://registry.yarnpkg.com/javascript-stringify/-/javascript-stringify-1.6.0.tgz#142d111f3a6e3dae8f4a9afd77d45855b5a9cce3"
 
+javascript-stringify@^2.0.0:
+  version "2.0.1"
+  resolved "https://registry.yarnpkg.com/javascript-stringify/-/javascript-stringify-2.0.1.tgz#6ef358035310e35d667c675ed63d3eb7c1aa19e5"
+  integrity sha512-yV+gqbd5vaOYjqlbk16EG89xB5udgjqQF3C5FAORDg4f/IS1Yc5ERCv5e/57yBcfJYw05V5JyIXabhwb75Xxow==
+
 jest-changed-files@^24.9.0:
   version "24.9.0"
   resolved "https://registry.yarnpkg.com/jest-changed-files/-/jest-changed-files-24.9.0.tgz#08d8c15eb79a7fa3fc98269bc14b451ee82f8039"
@@ -13218,13 +13223,21 @@ webidl-conversions@^4.0.2:
   resolved "https://registry.yarnpkg.com/webidl-conversions/-/webidl-conversions-4.0.2.tgz#a855980b1f0b6b359ba1d5d9fb39ae941faa63ad"
   integrity sha512-YQ+BmxuTgd6UXZW3+ICGfyqRyHXVlD5GtQr5+qjiNW7bF0cqrzX500HVXPBOvgXb5YnzDd+h0zqyv61KUD7+Sg==
 
-webpack-chain@^4.6.0, webpack-chain@^4.9.0:
+webpack-chain@^4.9.0:
   version "4.12.1"
   resolved "https://registry.yarnpkg.com/webpack-chain/-/webpack-chain-4.12.1.tgz#6c8439bbb2ab550952d60e1ea9319141906c02a6"
   dependencies:
     deepmerge "^1.5.2"
     javascript-stringify "^1.6.0"
 
+webpack-chain@^6.0.0:
+  version "6.0.0"
+  resolved "https://registry.yarnpkg.com/webpack-chain/-/webpack-chain-6.0.0.tgz#9c36525a1271a54e7bfd1791199b395f400ae4f1"
+  integrity sha512-NK62XgJOOSmYs4kaXFIKKeClpuOVHY7m6e4XwxbVX/2HAUboH6xFCTVXMVv8+jB6K8o/UGjlo1Cv3XXOyNAAGw==
+  dependencies:
+    deepmerge "^1.5.2"
+    javascript-stringify "^2.0.0"
+
 webpack-dev-middleware@^3.7.2:
   version "3.7.2"
   resolved "https://registry.yarnpkg.com/webpack-dev-middleware/-/webpack-dev-middleware-3.7.2.tgz#0019c3db716e3fa5cecbf64f2ab88a74bab331f3"