Bump async from 2.6.3 to 2.6.4 in /template/admin

Bumps [async](https://github.com/caolan/async) from 2.6.3 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/v2.6.3...v2.6.4)

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

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

template/admin/package-lock.json

@@ -2183,12 +2183,9 @@
       "dev": true
     },
     "async": {
-      "version": "2.6.3",
-      "resolved": "https://registry.npmjs.org/async/-/async-2.6.3.tgz",
-      "integrity": "sha512-zflvls11DCy+dQWzTW2dzuilv8Z5X/pjfmZOWba6TNIVDm+2UDaJmXSOXlasHKfNBs8oo3M0aT50fDEWfKZjXg==",
-      "requires": {
-        "lodash": "^4.17.14"
-      }
+      "version": "3.2.3",
+      "resolved": "https://registry.npmjs.org/async/-/async-3.2.3.tgz",
+      "integrity": "sha512-spZRyzKL5l5BZQrr/6m/SqFdBN0q3OCI0f9rjfBzCMBIP4p75P620rR3gTmaksNOhmzgdxcaxdNfMy6anrbM0g=="
     },
     "async-each": {
       "version": "1.0.3",
@@ -8377,6 +8374,17 @@
         "js-yaml": "^3.7.0",
         "mkdirp": "^0.5.1",
         "once": "^1.4.0"
+      },
+      "dependencies": {
+        "async": {
+          "version": "2.6.4",
+          "resolved": "https://registry.npmjs.org/async/-/async-2.6.4.tgz",
+          "integrity": "sha512-mzo5dfJYwAn29PeiJ0zvwTo04zj8HDJj0Mn8TD7sno7q12prdbnasKJHhkm2c1LgrhlJ0teaea8860oxi51mGA==",
+          "dev": true,
+          "requires": {
+            "lodash": "^4.17.14"
+          }
+        }
       }
     },
     "istanbul-lib-coverage": {
@@ -12666,6 +12674,15 @@
         "mkdirp": "^0.5.1"
       },
       "dependencies": {
+        "async": {
+          "version": "2.6.4",
+          "resolved": "https://registry.npmjs.org/async/-/async-2.6.4.tgz",
+          "integrity": "sha512-mzo5dfJYwAn29PeiJ0zvwTo04zj8HDJj0Mn8TD7sno7q12prdbnasKJHhkm2c1LgrhlJ0teaea8860oxi51mGA==",
+          "dev": true,
+          "requires": {
+            "lodash": "^4.17.14"
+          }
+        },
         "debug": {
           "version": "3.2.6",
           "resolved": "https://registry.npmjs.org/debug/-/debug-3.2.6.tgz",