fix: upgrade webpack from 4.18.0 to 4.43.0

Snyk has created this PR to upgrade webpack from 4.18.0 to 4.43.0.

See this package in npm:


See this project in Snyk:
https://app.snyk.io/org/tidepool/project/20c00306-8e92-463c-855a-94190c33943d?utm_source=github&utm_medium=upgrade-pr

Author: snyk-bot

package.json

@@ -138,7 +138,7 @@
     "style-loader": "0.23.0",
     "tidepool-standard-action": "0.1.1",
     "url-loader": "1.1.1",
-    "webpack": "4.18.0",
+    "webpack": "4.43.0",
     "webpack-cli": "3.1.0"
   },
   "peerDependencies": {