[Dependabot] Acorn Dependabot Update

Updates Acorn from 5.7.3 to 5.7.4, used in the react web app.

Commit log:

* Bump acorn from 5.7.3 to 5.7.4 in /onvm_web/react-app

onvm_web/react-app/yarn.lock

@@ -1057,9 +1057,9 @@ acorn-walk@^6.0.1:
   integrity sha512-ugTb7Lq7u4GfWSqqpwE0bGyoBZNMTok/zDBXxfEG0QM50jNlGhIWjRC1pPN7bvV1anhF+bs+/gNcRw+o55Evbg==
 
 acorn@^5.0.0, acorn@^5.0.3, acorn@^5.5.3, acorn@^5.6.0, acorn@^5.6.2, acorn@^5.7.1:
-  version "5.7.3"
-  resolved "https://registry.yarnpkg.com/acorn/-/acorn-5.7.3.tgz#67aa231bf8812974b85235a96771eb6bd07ea279"
-  integrity sha512-T/zvzYRfbVojPWahDsE5evJdHb3oJoQfFbsrKM7w5Zcs++Tr257tia3BmMP8XYVjp1S9RZXQMh7gao96BlqZOw==
+  version "5.7.4"
+  resolved "https://registry.yarnpkg.com/acorn/-/acorn-5.7.4.tgz#3e8d8a9947d0599a1796d10225d7432f4a4acf5e"
+  integrity sha512-1D++VG7BhrtvQpNbBzovKNc1FLGGEE/oGe7b9xJm/RFHMBeUaUGpluV9RLjZa47YFdPcDAenEYuq9pQPcMdLJg==
 
 acorn@^6.0.1:
   version "6.0.2"

onvm_web/web-build/asset-manifest.json

@@ -11,6 +11,6 @@
   "static/css/main.467df24c.chunk.css.map": "/static/css/main.467df24c.chunk.css.map",
   "static/css/1.983b9b6a.chunk.css.map": "/static/css/1.983b9b6a.chunk.css.map",
   "index.html": "/index.html",
-  "precache-manifest.066f61a06c4d9a9b74e77de8ce55ef9c.js": "/precache-manifest.066f61a06c4d9a9b74e77de8ce55ef9c.js",
+  "precache-manifest.9e30993647e06e9411d5539e546b5a8f.js": "/precache-manifest.9e30993647e06e9411d5539e546b5a8f.js",
   "service-worker.js": "/service-worker.js"
 }