fix: Add jvm target compatibility to Kotlin plugins

[davidmartos96]

Description

When using Gradle 8+ and Kotlin version 1.8+, the build fails with the following error.
(Using the recently uploaded versions of the plugins)

I believe the correct fix is to indicate the jvmTarget in the kotlinOptions to all plugins that use Kotlin, same as it is done for the compileOptions with Java

kotlinOptions {
    jvmTarget = '1.8'
}

Should the compileOptions be kept in Kotlin plugins as well?

compileOptions {
    sourceCompatibility JavaVersion.VERSION_1_8
    targetCompatibility JavaVersion.VERSION_1_8
}

Checklist

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• I titled the PR using Conventional Commits.
• I did not modify the CHANGELOG.md nor the plugin version in pubspec.yaml files.
• All existing and new tests are passing.
• The analyzer (flutter analyze) does not report any problems on my PR.

Breaking Change

Does your PR require plugin users to manually update their apps to accommodate your change?

• Yes, this is a breaking change (please indicate that with a ! in the title as explained in Conventional Commits).
• No, this is not a breaking change.

[vbuberen]

Good catch. It is due to using JDK 17 with switch to AGP 8 + Gradle 8. Forgot to add it while was adding target for Java recently. Thanks for opening a PR.