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

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

package.json

@@ -53,7 +53,7 @@
     "i18n": "^0.8.3",
     "imgur": "git+https://github.com/hackmdio/node-imgur.git",
     "ionicons": "~2.0.1",
-    "jquery": "^3.4.1",
+    "jquery": "^3.5.0",
     "jquery-mousewheel": "^3.1.13",
     "jquery-ui": "^1.12.1",
     "js-cookie": "^2.1.3",