Adds a TODOs Badge to the README (#11999)

Closes #11210

Co-authored-by: Lauris BH <lauris@nix.lv>

README.md

@@ -13,6 +13,7 @@
 [![Become a backer/sponsor of gitea](https://opencollective.com/gitea/tiers/backers/badge.svg?label=backers&color=brightgreen)](https://opencollective.com/gitea)
 [![License: MIT](https://img.shields.io/badge/License-MIT-blue.svg)](https://opensource.org/licenses/MIT)
 [![Crowdin](https://badges.crowdin.net/gitea/localized.svg)](https://crowdin.com/project/gitea)
+[![TODOs](https://badgen.net/https/api.tickgit.com/badgen/github.com/go-gitea/gitea)](https://www.tickgit.com/browse?repo=github.com/go-gitea/gitea)
 
 ## Purpose