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

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JS-JQUERY-174006

package-lock.json

@@ -2116,9 +2116,9 @@
       "dev": true
     },
     "jquery": {
-      "version": "3.3.1",
-      "resolved": "https://registry.npmjs.org/jquery/-/jquery-3.3.1.tgz",
-      "integrity": "sha512-Ubldcmxp5np52/ENotGxlLe6aGMvmF4R8S6tZjsP6Knsaxd/xp3Zrh50cG93lR6nPXyUFwzN3ZSOQI0wRJNdGg=="
+      "version": "3.4.0",
+      "resolved": "https://registry.npmjs.org/jquery/-/jquery-3.4.0.tgz",
+      "integrity": "sha512-ggRCXln9zEqv6OqAGXFEcshF5dSBvCkzj6Gm2gzuR5fWawaX8t7cxKVkkygKODrDAzKdoYw3l/e3pm3vlT4IbQ=="
     },
     "js-tokens": {
       "version": "3.0.2",

package.json

@@ -17,7 +17,7 @@
     "@fortawesome/fontawesome-free": "5.7.2",
     "bootstrap": "4.3.1",
     "clipboard": "2.0.4",
-    "jquery": "3.3.1",
+    "jquery": "3.4.0",
     "lg-thumbnail": "1.1.0",
     "lightgallery": "1.6.11",
     "mermaid": "8.0.0"