fix: upgrade @aws-amplify/core from 3.3.2 to 3.3.3 (#90)

Snyk has created this PR to upgrade @aws-amplify/core from 3.3.2 to 3.3.3.

See this package in NPM:
https://www.npmjs.com/package/@aws-amplify/core

See this project in Snyk:
https://app.snyk.io/org/johanneskonings/project/b30410ce-f052-409e-904e-a2e4798c61db?utm_source=github&utm_medium=upgrade-pr

Co-authored-by: Johannes Konings <johannes.konings@outlook.com>

package.json

@@ -6,7 +6,7 @@
   "main": "dist/index.js",
   "dependencies": {
     "@aws-amplify/auth": "^3.2.13",
-    "@aws-amplify/core": "^3.3.2",
+    "@aws-amplify/core": "^3.3.3",
     "@aws-amplify/ui-react": "^0.2.8",
     "@date-io/date-fns": "^1.3.13",
     "@material-ui/core": "4.10.1",