Bump lodash from 4.17.15 to 4.17.21 in /admin

Bumps [lodash](https://github.com/lodash/lodash) from 4.17.15 to 4.17.21.
- [Release notes](https://github.com/lodash/lodash/releases)
- [Commits](https://github.com/lodash/lodash/compare/4.17.15...4.17.21)

Signed-off-by: dependabot[bot] <support@github.com>

admin/yarn.lock

@@ -4842,9 +4842,9 @@ lodash.uniq@^4.5.0:
   integrity sha1-0CJTc662Uq3BvILklFM5qEJ1R3M=
 
 lodash@^4.17.11, lodash@^4.17.12, lodash@^4.17.13, lodash@^4.17.14, lodash@^4.17.15, lodash@^4.17.3, lodash@^4.17.4, lodash@^4.17.5, lodash@^4.3.0:
-  version "4.17.15"
-  resolved "https://registry.npm.taobao.org/lodash/download/lodash-4.17.15.tgz#b447f6670a0455bbfeedd11392eff330ea097548"
-  integrity sha1-tEf2ZwoEVbv+7dETku/zMOoJdUg=
+  version "4.17.21"
+  resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.21.tgz#679591c564c3bffaae8454cf0b3df370c3d6911c"
+  integrity sha512-v2kDEe57lecTulaDIuNTPy3Ry4gLGJ6Z1O3vE1krgXZNrsQ+LFTGHVxVjcXPs17LhbZVGedAJv8XZ1tvj5FvSg==
 
 log-symbols@^2.2.0:
   version "2.2.0"