build: update webpack-merge to version 4.2.1

Author: renovate-bot

packages/angular_devkit/build_angular/package.json

@@ -48,7 +48,7 @@
     "webpack": "4.28.2",
     "webpack-dev-middleware": "3.5.0",
     "webpack-dev-server": "3.1.14",
-    "webpack-merge": "4.1.5",
+    "webpack-merge": "4.2.1",
     "webpack-sources": "1.3.0",
     "webpack-subresource-integrity": "1.1.0-rc.6"
   },

yarn.lock

@@ -10430,10 +10430,10 @@ webpack-log@^2.0.0:
     ansi-colors "^3.0.0"
     uuid "^3.3.2"
 
-webpack-merge@4.1.5:
-  version "4.1.5"
-  resolved "https://registry.yarnpkg.com/webpack-merge/-/webpack-merge-4.1.5.tgz#2be31e846c20767d1bef56bdca64c328a681190a"
-  integrity sha512-sVcM+MMJv6DO0C0GLLltx8mUlGMKXE0zBsuMqZ9jz2X9gsekALw6Rs0cAfTWc97VuWS6NpVUa78959zANnMMLQ==
+webpack-merge@4.2.1:
+  version "4.2.1"
+  resolved "https://registry.yarnpkg.com/webpack-merge/-/webpack-merge-4.2.1.tgz#5e923cf802ea2ace4fd5af1d3247368a633489b4"
+  integrity sha512-4p8WQyS98bUJcCvFMbdGZyZmsKuWjWVnVHnAS3FFg0HDaRVrPbkivx2RYCre8UiemD67RsiFFLfn4JhLAin8Vw==
   dependencies:
     lodash "^4.17.5"