Bump com.github.triplet.play from 3.7.0 to 3.8.4

Bumps com.github.triplet.play from 3.7.0 to 3.8.4.

---
updated-dependencies:
- dependency-name: com.github.triplet.play
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

uhabits-android/build.gradle.kts

@@ -18,7 +18,7 @@
  */
 
 plugins {
-    id("com.github.triplet.play") version "3.7.0"
+    id("com.github.triplet.play") version "3.8.4"
     id("com.android.application") version "7.4.2"
     id("org.jetbrains.kotlin.android")
     id("org.jetbrains.kotlin.kapt")