chore: bump version to 0.28.0

Author: DenverCoder1

composer.json

@@ -10,7 +10,7 @@
     "stats"
   ],
   "license": "MIT",
-  "version": "0.27.0",
+  "version": "0.28.0",
   "homepage": "https://github.com/DenverCoder1/github-readme-streak-stats",
   "autoload": {
     "classmap": [