deal with security alerts

package.json

@@ -45,7 +45,7 @@
     "d3plus-text": "0.9.25",
     "fuse.js": "^3.0.0",
     "history": "^4.6.1",
-    "lodash": "^4.17.4",
+    "lodash": "4.17.13",
     "markdown": "^0.5.0",
     "moment": "^2.17.1",
     "mozilla-fira-pack": "^0.0.1",

yarn.lock

@@ -5545,6 +5545,11 @@ [email protected], lodash@^4.17.11, lodash@^4.17.3, lodash@^4.17.4, lodash@^4.17.5,
   resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.11.tgz#b39ea6229ef607ecd89e2c8df12536891cac9b8d"
   integrity sha512-cQKh8igo5QUhZ7lg38DYWAxMvjSAKG0A8wGSVimP07SIUEK2UO+arSRKbRZWtelMtN5V0Hkwh5ryOto/SshYIg==
 
+[email protected]:
+  version "4.17.13"
+  resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.13.tgz#0bdc3a6adc873d2f4e0c4bac285df91b64fc7b93"
+  integrity sha512-vm3/XWXfWtRua0FkUyEHBZy8kCPjErNBT9fJx8Zvs+U6zjqPbTUOpkaoum3O5uiA8sm+yNMHXfYkTUHFoMxFNA==
+
 lodash@^3.10.0:
   version "3.10.1"
   resolved "https://registry.yarnpkg.com/lodash/-/lodash-3.10.1.tgz#5bf45e8e49ba4189e17d482789dfd15bd140b7b6"