Bump acorn from 5.7.3 to 5.7.4

Bumps [acorn](https://github.com/acornjs/acorn) from 5.7.3 to 5.7.4.
- [Release notes](https://github.com/acornjs/acorn/releases)
- [Commits](acornjs/acorn@5.7.3...5.7.4)

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

Author: dependabot[bot]

yarn.lock

@@ -2568,14 +2568,10 @@ acorn-walk@^6.0.1:
   resolved "https://packages.atlassian.com/api/npm/npm-remote/acorn-walk/-/acorn-walk-6.1.1.tgz#d363b66f5fac5f018ff9c3a1e7b6f8e310cc3913"
 
 acorn@^5.5.3:
-  version "5.7.3"
-  resolved "https://packages.atlassian.com/api/npm/npm-remote/acorn/-/acorn-5.7.3.tgz#67aa231bf8812974b85235a96771eb6bd07ea279"
+  version "5.7.4"
+  resolved "https://registry.yarnpkg.com/acorn/-/acorn-5.7.4.tgz#3e8d8a9947d0599a1796d10225d7432f4a4acf5e"
 
-acorn@^6.0.1:
-  version "6.1.0"
-  resolved "https://packages.atlassian.com/api/npm/npm-remote/acorn/-/acorn-6.1.0.tgz#b0a3be31752c97a0f7013c5f4903b71a05db6818"
-
-acorn@^6.0.5, acorn@^6.0.7, acorn@^6.1.1:
+acorn@^6.0.1, acorn@^6.0.5, acorn@^6.0.7, acorn@^6.1.1:
   version "6.1.1"
   resolved "https://registry.yarnpkg.com/acorn/-/acorn-6.1.1.tgz#7d25ae05bb8ad1f9b699108e1094ecd7884adc1f"