Bump the all-deps group with 2 updates

Bumps the all-deps group with 2 updates: [jvm](https://github.com/JetBrains/kotlin) and [plugin.serialization](https://github.com/JetBrains/kotlin).


Updates `jvm` from 1.9.20 to 1.9.21
- [Release notes](https://github.com/JetBrains/kotlin/releases)
- [Changelog](https://github.com/JetBrains/kotlin/blob/master/ChangeLog.md)
- [Commits](JetBrains/kotlin@v1.9.20...v1.9.21)

Updates `plugin.serialization` from 1.9.20 to 1.9.21
- [Release notes](https://github.com/JetBrains/kotlin/releases)
- [Changelog](https://github.com/JetBrains/kotlin/blob/master/ChangeLog.md)
- [Commits](JetBrains/kotlin@v1.9.20...v1.9.21)

---
updated-dependencies:
- dependency-name: jvm
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: all-deps
- dependency-name: plugin.serialization
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: all-deps
...

Signed-off-by: dependabot[bot] <[email protected]>

build.gradle.kts

@@ -15,8 +15,8 @@ group = "io.nais"
 version = "generatedlater"
 
 plugins {
-   kotlin("jvm") version "1.9.20"
-   kotlin("plugin.serialization") version "1.9.20"
+   kotlin("jvm") version "1.9.21"
+   kotlin("plugin.serialization") version "1.9.21"
    id("com.github.johnrengelman.shadow") version "8.1.1"
    id("com.github.ben-manes.versions") version "0.50.0"
    id("org.cyclonedx.bom") version "1.8.1"