Bump acorn from 5.7.1 to 5.7.4 in /Example (#652)

Bumps [acorn](https://github.com/acornjs/acorn) from 5.7.1 to 5.7.4.
- [Release notes](https://github.com/acornjs/acorn/releases)
- [Commits](acornjs/acorn@5.7.1...5.7.4)

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

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

Example/yarn.lock

@@ -1664,8 +1664,9 @@ acorn-jsx@^5.0.2:
   integrity sha512-tiNTrP1MP0QrChmD2DdupCr6HWSFeKVw5d/dHTu4Y7rkAkRhU/Dt7dphAfIUyxtHpl/eBVip5uTNSpQJHylpAw==
 
 acorn@^5.0.0, acorn@^5.3.0:
-  version "5.7.1"
-  resolved "https://registry.yarnpkg.com/acorn/-/acorn-5.7.1.tgz#f095829297706a7c9776958c0afc8930a9b9d9d8"
+  version "5.7.4"
+  resolved "https://registry.yarnpkg.com/acorn/-/acorn-5.7.4.tgz#3e8d8a9947d0599a1796d10225d7432f4a4acf5e"
+  integrity sha512-1D++VG7BhrtvQpNbBzovKNc1FLGGEE/oGe7b9xJm/RFHMBeUaUGpluV9RLjZa47YFdPcDAenEYuq9pQPcMdLJg==
 
 acorn@^7.0.0:
   version "7.1.0"