Update dependency mkdirp to v1

Author: renovate-bot

package.json

@@ -131,7 +131,7 @@
         "merge2": "^1.2.1",
         "mini-css-extract-plugin": "^0.9.0",
         "minimist": "^1.2.0",
-        "mkdirp": "^0.5.1",
+        "mkdirp": "^1.0.0",
         "mockdate": "^2.0.2",
         "nprogress": "^0.2.0",
         "optimize-css-assets-webpack-plugin": "^5.0.1",