Chore: Upgrade dependencies to latest versions.

package.json

@@ -14,21 +14,21 @@
   "devDependencies": {
     "browser-sync": "^2.24.5",
     "cheerio": "^1.0.0-rc.3",
-    "date-format": "^2.0.0",
+    "date-format": "^3.0.0",
     "fancy-log": "^1.3.3",
-    "feed": "^3.0.0",
+    "feed": "^4.0.0",
     "fs-extra": "^8.1.0",
-    "gitlab": "^4.3.0",
+    "gitlab": "^12.0.1",
     "gulp": "^4.0.0",
     "gulp-htmlclean": "^2.7.22",
     "gulp-pug": "^4.0.1",
     "gulp-sass": "^4.0.1",
     "klaw-sync": "^6.0.0",
-    "merge2": "^1.2.3",
-    "stylelint": "^10.1.0",
+    "merge2": "^1.3.0",
+    "stylelint": "^12.0.0",
     "stylelint-config-xo-scss": "^0.9.0",
     "stylelint-config-xo-space": "^0.13.0",
-    "xo": "^0.24.0"
+    "xo": "^0.25.3"
   },
   "stylelint": {
     "extends": [