Bump acorn from 7.1.0 to 7.4.0 (#448)

Bumps [acorn](https://github.com/acornjs/acorn) from 7.1.0 to 7.4.0.
- [Release notes](https://github.com/acornjs/acorn/releases)
- [Commits](acornjs/acorn@7.1.0...7.4.0)

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

yarn.lock

@@ -61,9 +61,9 @@ acorn-jsx@^5.0.2:
   integrity sha512-tiNTrP1MP0QrChmD2DdupCr6HWSFeKVw5d/dHTu4Y7rkAkRhU/Dt7dphAfIUyxtHpl/eBVip5uTNSpQJHylpAw==
 
 acorn@^7.0.0:
-  version "7.1.0"
-  resolved "https://registry.yarnpkg.com/acorn/-/acorn-7.1.0.tgz#949d36f2c292535da602283586c2477c57eb2d6c"
-  integrity sha512-kL5CuoXA/dgxlBbVrflsflzQ3PAas7RYZB52NOm/6839iVYJgKMJ3cQJD+t2i5+qFa8h3MDpEOJiS64E8JLnSQ==
+  version "7.4.0"
+  resolved "https://registry.yarnpkg.com/acorn/-/acorn-7.4.0.tgz#e1ad486e6c54501634c6c397c5c121daa383607c"
+  integrity sha512-+G7P8jJmCHr+S+cLfQxygbWhXy+8YTVGzAkpEbcLo2mLoL7tij/VG41QSHACSf5QgYRhMZYHuNc6drJaO0Da+w==
 
 ajv@^6.10.0, ajv@^6.10.2:
   version "6.10.2"