Bump kotlin from 2.0.20 to 2.0.21

Bumps `kotlin` from 2.0.20 to 2.0.21.

Updates `org.jetbrains.kotlin.android` from 2.0.20 to 2.0.21

Updates `org.jetbrains.kotlin.plugin.compose` from 2.0.20 to 2.0.21

---
updated-dependencies:
- dependency-name: org.jetbrains.kotlin.android
  dependency-type: direct:production
  update-type: version-update:semver-patch
- dependency-name: org.jetbrains.kotlin.plugin.compose
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

gradle/libs.versions.toml

@@ -15,7 +15,7 @@ androidxLifecycle = "2.8.6"
 androidxNavigation = "2.5.0"
 androidxTest = "1.6.1"
 androidxJunit = "1.2.1"
-kotlin = "2.0.20"
+kotlin = "2.0.21"
 kotlinxCoroutines = "1.9.0"
 okhttp = "4.12.0"
 retrofit = "2.9.0"