chore(deps): update dependency acorn to v8

Author: renovate[bot]

package.json

@@ -32,7 +32,7 @@
     "url": "https://github.com/CondeNast/perf-timeline-cli.git"
   },
   "devDependencies": {
-    "acorn": "6.1.1",
+    "acorn": "8.12.0",
     "eslint": "5.15.3",
     "eslint-config-airbnb-base": "13.1.0",
     "eslint-plugin-import": "2.16.0",