[Security] Bump acorn from 6.4.0 to 6.4.1 in /example/browser

Bumps [acorn](https://github.com/acornjs/acorn) from 6.4.0 to 6.4.1. **This update includes a security fix.**
- [Release notes](https://github.com/acornjs/acorn/releases)
- [Commits](https://github.com/acornjs/acorn/compare/6.4.0...6.4.1)

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

example/browser/package-lock.json

@@ -192,9 +192,9 @@
       "dev": true
     },
     "acorn": {
-      "version": "6.4.0",
-      "resolved": "https://registry.npmjs.org/acorn/-/acorn-6.4.0.tgz",
-      "integrity": "sha512-gac8OEcQ2Li1dxIEWGZzsp2BitJxwkwcOm0zHAJLcPJaVvm58FRnk6RkuLRpU1EujipU2ZFODv2P9DLMfnV8mw==",
+      "version": "6.4.1",
+      "resolved": "https://registry.npmjs.org/acorn/-/acorn-6.4.1.tgz",
+      "integrity": "sha512-ZVA9k326Nwrj3Cj9jlh3wGFutC2ZornPNARZwsNYqQYgN0EsV2d53w5RN/co65Ohn4sUAUtb1rSUAOD6XN9idA==",
       "dev": true
     },
     "ajv": {
@@ -3621,25 +3621,12 @@
           "resolved": "https://registry.npmjs.org/abab/-/abab-2.0.0.tgz",
           "integrity": "sha512-sY5AXXVZv4Y1VACTtR11UJCPHHudgY5i26Qj5TypE6DKlIApbwb5uqhXcJ5UUGbvZNRh7EeIoW+LrJumBsKp7w=="
         },
-        "acorn": {
-          "version": "7.1.0",
-          "resolved": "https://registry.npmjs.org/acorn/-/acorn-7.1.0.tgz",
-          "integrity": "sha512-kL5CuoXA/dgxlBbVrflsflzQ3PAas7RYZB52NOm/6839iVYJgKMJ3cQJD+t2i5+qFa8h3MDpEOJiS64E8JLnSQ=="
-        },
         "acorn-globals": {
           "version": "4.3.4",
           "resolved": "https://registry.npmjs.org/acorn-globals/-/acorn-globals-4.3.4.tgz",
           "integrity": "sha512-clfQEh21R+D0leSbUdWf3OcfqyaCSAQ8Ryq00bofSekfr9W8u1jyYZo6ir0xu9Gtcf7BjcHJpnbZH7JOCpP60A==",
           "requires": {
-            "acorn": "^6.0.1",
             "acorn-walk": "^6.0.1"
-          },
-          "dependencies": {
-            "acorn": {
-              "version": "6.2.1",
-              "resolved": "https://registry.npmjs.org/acorn/-/acorn-6.2.1.tgz",
-              "integrity": "sha512-JD0xT5FCRDNyjDda3Lrg/IxFscp9q4tiYtxE1/nOzlKCk7hIRuYjhq1kCNkbPjMRMZuFq20HNQn1I9k8Oj0E+Q=="
-            }
           }
         },
         "acorn-jsx": {
@@ -4718,7 +4705,6 @@
           "resolved": "https://registry.npmjs.org/espree/-/espree-6.1.2.tgz",
           "integrity": "sha512-2iUPuuPP+yW1PZaMSDM9eyVf8D5P0Hi8h83YtZ5bPc/zHYjII5khoixIUTMO794NOY8F/ThF1Bo8ncZILarUTA==",
           "requires": {
-            "acorn": "^7.1.0",
             "acorn-jsx": "^5.1.0",
             "eslint-visitor-keys": "^1.1.0"
           }
@@ -6226,7 +6212,6 @@
           "integrity": "sha512-fAl1W0/7T2G5vURSyxBzrJ1LSdQn6Tr5UX/xD4PXDx/PDgwygedfW6El/KIj3xJ7FU61TTYnc/l/B7P49Eqt6g==",
           "requires": {
             "abab": "^2.0.0",
-            "acorn": "^7.1.0",
             "acorn-globals": "^4.3.2",
             "array-equal": "^1.0.0",
             "cssom": "^0.4.1",