chore(deps-dev): bump acorn from 6.2.1 to 6.3.0

Bumps [acorn](https://github.com/acornjs/acorn) from 6.2.1 to 6.3.0.
- [Release notes](https://github.com/acornjs/acorn/releases)
- [Commits](https://github.com/acornjs/acorn/compare/6.2.1...6.3.0)

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

web3.js/package-lock.json

@@ -4330,9 +4330,9 @@
       }
     },
     "acorn": {
-      "version": "6.2.1",
-      "resolved": "https://registry.npmjs.org/acorn/-/acorn-6.2.1.tgz",
-      "integrity": "sha512-JD0xT5FCRDNyjDda3Lrg/IxFscp9q4tiYtxE1/nOzlKCk7hIRuYjhq1kCNkbPjMRMZuFq20HNQn1I9k8Oj0E+Q==",
+      "version": "6.3.0",
+      "resolved": "https://registry.npmjs.org/acorn/-/acorn-6.3.0.tgz",
+      "integrity": "sha512-/czfa8BwS88b9gWQVhc8eknunSA2DoJpJyTQkhheIf5E48u1N0R4q/YxxsAeqRrmK9TQ/uYfgLDfZo91UlANIA==",
       "dev": true
     },
     "acorn-globals": {