fix: package.json & package-lock.json to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JS-JQUERY-565129
- https://snyk.io/vuln/SNYK-JS-JQUERY-567880

Author: snyk-bot

package-lock.json

@@ -7,7 +7,7 @@
     "private": true,
     "dependencies": {
         "core-js": "^3.2.1",
-        "jquery": "^3.4.1"
+        "jquery": "^3.5.0"
     },
     "devDependencies": {
         "clean-webpack-plugin": "^3.0.0",