Bump lodash from 4.17.20 to 4.17.21

Bumps [lodash](https://github.com/lodash/lodash) from 4.17.20 to 4.17.21.
- [Release notes](https://github.com/lodash/lodash/releases)
- [Commits](lodash/lodash@4.17.20...4.17.21)

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

package.json

@@ -6,7 +6,7 @@
   "dependencies": {
     "file-saver": "^1.3.3",
     "linkurious": "^1.5.2",
-    "lodash": "^4.17.13",
+    "lodash": "^4.17.21",
     "react": "15.3.2",
     "react-dom": "15.3.2"
   },

yarn.lock

@@ -3133,9 +3133,9 @@ lodash@^3.10.0:
   version "3.10.1"
   resolved "https://registry.yarnpkg.com/lodash/-/lodash-3.10.1.tgz#5bf45e8e49ba4189e17d482789dfd15bd140b7b6"
 
-lodash@^4.0.0, lodash@^4.13.1, lodash@^4.17.13, lodash@^4.17.14, lodash@^4.17.15, lodash@^4.17.5, lodash@^4.2.0, lodash@~4.17.10:
-  version "4.17.20"
-  resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.20.tgz#b44a9b6297bcb698f1c51a3545a2b3b368d59c52"
+lodash@^4.0.0, lodash@^4.13.1, lodash@^4.17.14, lodash@^4.17.15, lodash@^4.17.21, lodash@^4.17.5, lodash@^4.2.0, lodash@~4.17.10:
+  version "4.17.21"
+  resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.21.tgz#679591c564c3bffaae8454cf0b3df370c3d6911c"
 
 loglevel@^1.4.1:
   version "1.6.3"