chore(deps-dev): bump acorn from 6.1.1 to 6.2.0

Bumps [acorn](https://github.com/acornjs/acorn) from 6.1.1 to 6.2.0.
- [Release notes](https://github.com/acornjs/acorn/releases)
- [Commits](https://github.com/acornjs/acorn/compare/6.1.1...6.2.0)

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

web3.js/package-lock.json

@@ -3927,9 +3927,9 @@
       }
     },
     "acorn": {
-      "version": "6.1.1",
-      "resolved": "https://registry.npmjs.org/acorn/-/acorn-6.1.1.tgz",
-      "integrity": "sha512-jPTiwtOxaHNaAPg/dmrJ/beuzLRnXtB0kQPQ8JpotKJgTB6rX6c8mlf315941pyjBSaPg8NHXS9fhP4u17DpGA==",
+      "version": "6.2.0",
+      "resolved": "https://registry.npmjs.org/acorn/-/acorn-6.2.0.tgz",
+      "integrity": "sha512-8oe72N3WPMjA+2zVG71Ia0nXZ8DpQH+QyyHO+p06jT8eg8FGG3FbcUIi8KziHlAfheJQZeoqbvq1mQSQHXKYLw==",
       "dev": true
     },
     "acorn-globals": {