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

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JS-BRACES-6838727
- https://snyk.io/vuln/SNYK-JS-GLOBPARENT-1016905

package.json

@@ -92,7 +92,7 @@
     "revalidator": "^0.3.1",
     "rimraf": "^3.0.0",
     "rss-parser": "^3.12.0",
-    "sass": "^1.26.3",
+    "sass": "^1.79.0",
     "sass-loader": "^9.0.2",
     "search-with-your-keyboard": "1.1.0",
     "semver": "^5.7.1",