Update changelog for 2025.8.4

Author: jesserockz

content/changelog/2025.8.0.md

@@ -209,6 +209,17 @@ or advanced configurations may need updates.
 
 </details>
 
+## Release 2025.8.4 - September 10
+
+<details open>
+<summary></summary>
+
+- [sen5x] Fix initialization [esphome#10603](https://github.com/esphome/esphome/pull/10603) by [@kbx81](https://github.com/kbx81)
+- [kmeteriso] Fix i2c call [esphome#10618](https://github.com/esphome/esphome/pull/10618) by [@clydebarrow](https://github.com/clydebarrow)
+- [light] add missing header [esphome#10590](https://github.com/esphome/esphome/pull/10590) by [@tomaszduda23](https://github.com/tomaszduda23)
+
+</details>
+
 ## Full list of changes
 
 ### New Features