Bump acorn from 6.1.1 to 6.4.1

Bumps [acorn](https://github.com/acornjs/acorn) from 6.1.1 to 6.4.1.
- [Release notes](https://github.com/acornjs/acorn/releases)
- [Commits](https://github.com/acornjs/acorn/compare/6.1.1...6.4.1)

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

package-lock.json

@@ -111,9 +111,9 @@
       }
     },
     "acorn": {
-      "version": "6.1.1",
-      "resolved": "https://registry.npmjs.org/acorn/-/acorn-6.1.1.tgz",
-      "integrity": "sha512-jPTiwtOxaHNaAPg/dmrJ/beuzLRnXtB0kQPQ8JpotKJgTB6rX6c8mlf315941pyjBSaPg8NHXS9fhP4u17DpGA==",
+      "version": "7.1.1",
+      "resolved": "https://registry.npmjs.org/acorn/-/acorn-7.1.1.tgz",
+      "integrity": "sha512-add7dgA5ppRPxCFJoAGfMDi7PIBXq1RtGo7BhbLaxwrXPOmw8gq48Y9ozT01hUKy9byMjlR20EJhu5zlkErEkg==",
       "dev": true
     },
     "acorn-jsx": {
@@ -874,6 +874,14 @@
         "acorn": "^6.0.2",
         "acorn-jsx": "^5.0.0",
         "eslint-visitor-keys": "^1.0.0"
+      },
+      "dependencies": {
+        "acorn": {
+          "version": "6.4.1",
+          "resolved": "https://registry.npmjs.org/acorn/-/acorn-6.4.1.tgz",
+          "integrity": "sha512-ZVA9k326Nwrj3Cj9jlh3wGFutC2ZornPNARZwsNYqQYgN0EsV2d53w5RN/co65Ohn4sUAUtb1rSUAOD6XN9idA==",
+          "dev": true
+        }
       }
     },
     "esprima": {
@@ -1887,14 +1895,6 @@
         "@types/estree": "*",
         "@types/node": "*",
         "acorn": "^7.1.0"
-      },
-      "dependencies": {
-        "acorn": {
-          "version": "7.1.0",
-          "resolved": "https://registry.npmjs.org/acorn/-/acorn-7.1.0.tgz",
-          "integrity": "sha512-kL5CuoXA/dgxlBbVrflsflzQ3PAas7RYZB52NOm/6839iVYJgKMJ3cQJD+t2i5+qFa8h3MDpEOJiS64E8JLnSQ==",
-          "dev": true
-        }
       }
     },
     "rollup-cli": {