Bump async from 2.6.0 to 2.6.4

Bumps [async](https://github.com/caolan/async) from 2.6.0 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/v2.6.0...v2.6.4)

---
updated-dependencies:
- dependency-name: async
  dependency-type: direct:production
...

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

package-lock.json

@@ -26,11 +26,11 @@
             "integrity": "sha1-8S4PPF13sLHN2RRpQuTpbB5N1SU="
         },
         "async": {
-            "version": "2.6.0",
-            "resolved": "https://registry.npmjs.org/async/-/async-2.6.0.tgz",
-            "integrity": "sha512-xAfGg1/NTLBBKlHFmnd7PlmUW9KhVQIUuSrYem9xzFUZy13ScvtyGGejaae9iAVRiRq9+Cx7DPFaAAhCpyxyPw==",
+            "version": "2.6.4",
+            "resolved": "https://registry.npmjs.org/async/-/async-2.6.4.tgz",
+            "integrity": "sha512-mzo5dfJYwAn29PeiJ0zvwTo04zj8HDJj0Mn8TD7sno7q12prdbnasKJHhkm2c1LgrhlJ0teaea8860oxi51mGA==",
             "requires": {
-                "lodash": "^4.14.0"
+                "lodash": "^4.17.14"
             }
         },
         "asynckit": {
@@ -324,9 +324,9 @@
             }
         },
         "lodash": {
-            "version": "4.17.15",
-            "resolved": "https://registry.npmjs.org/lodash/-/lodash-4.17.15.tgz",
-            "integrity": "sha512-8xOcRHvCjnocdS5cpwXQXVzmmh5e5+saE2QGoeQmbKmRS6J3VQppPOIt0MnmE+4xlZoumy0GPG0D0MVIQbNA1A=="
+            "version": "4.17.21",
+            "resolved": "https://registry.npmjs.org/lodash/-/lodash-4.17.21.tgz",
+            "integrity": "sha512-v2kDEe57lecTulaDIuNTPy3Ry4gLGJ6Z1O3vE1krgXZNrsQ+LFTGHVxVjcXPs17LhbZVGedAJv8XZ1tvj5FvSg=="
         },
         "md5.js": {
             "version": "1.3.4",

package.json

@@ -8,7 +8,7 @@
         "url": "git+https://gitlab.com/aureolin/lbry-social-tipbot.git"
     },
     "dependencies": {
-        "async": "^2.5.0",
+        "async": "^2.6.4",
         "bs58check": "^2.0.2",
         "moment": "^2.18.1",
         "mysql": "^2.14.1",