Merge pull request #103 from silverstripe/dependabot/npm_and_yarn/async-2.6.4

Bumps [async](https://github.com/caolan/async) from 2.5.0 to 2.6.4.
- [Release notes](https://github.com/caolan/async/releases)
- [Changelog](https://github.com/caolan/async/blob/v2.6.4/CHANGELOG.md)
- [Commits](https://github.com/caolan/async/compare/v2.5.0...v2.6.4)

---
updated-dependencies:
- dependency-name: async
  dependency-type: indirect
...

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

yarn.lock

@@ -312,10 +312,10 @@ async-foreach@^0.1.3:
   resolved "https://registry.yarnpkg.com/async-foreach/-/async-foreach-0.1.3.tgz#36121f845c0578172de419a97dbeb1d16ec34542"
 
 async@^2.1.2, async@^2.1.4, async@^2.1.5:
-  version "2.5.0"
-  resolved "https://registry.yarnpkg.com/async/-/async-2.5.0.tgz#843190fd6b7357a0b9e1c956edddd5ec8462b54d"
+  version "2.6.4"
+  resolved "https://registry.yarnpkg.com/async/-/async-2.6.4.tgz#706b7ff6084664cd7eae713f6f965433b5504221"
   dependencies:
-    lodash "^4.14.0"
+    lodash "^4.17.14"
 
 asynckit@^0.4.0:
   version "0.4.0"
@@ -3723,9 +3723,9 @@ lodash@4.17.4:
   version "4.17.4"
   resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.4.tgz#78203a4d1c328ae1d86dca6460e369b57f4055ae"
 
-lodash@^4.0.0, lodash@^4.14.0, lodash@^4.17.15, lodash@^4.17.4, lodash@^4.2.0, lodash@^4.3.0, 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@^4.17.14, lodash@^4.17.15, lodash@^4.17.4, lodash@^4.2.0, lodash@^4.3.0, lodash@~4.17.10:
+  version "4.17.21"
+  resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.21.tgz#679591c564c3bffaae8454cf0b3df370c3d6911c"
 
 longest@^1.0.1:
   version "1.0.1"