📚 Fix commit activity (#34)

Author: sinclairpaul

README.md

@@ -99,7 +99,7 @@ SOFTWARE.
 [buymeacoffee-shield]: https://www.buymeacoffee.com/assets/img/guidelines/download-assets-sm-2.svg
 [buymeacoffee]: https://www.buymeacoffee.com/sinclairpaul
 [commits-shield]: https://img.shields.io/github/commit-activity/y/hassio-addons/addon-bookstack.svg
-[commits]: https://github.com/hassio-addons/addon-bookstack/commits/master
+[commits]: https://github.com/hassio-addons/addon-bookstack/commits/main
 [contributors]: https://github.com/hassio-addons/addon-bookstack/graphs/contributors
 [discord-ha]: https://discord.gg/c5DvZ4e
 [discord-shield]: https://img.shields.io/discord/478094546522079232.svg