Upgrade to kotlin-stdlib instead of kotlin-stdlib-jdk8 on Kotlin 1.8+

[techwn]

With Kotlin 1.8 + , the min JVM target is 1.8. So the Kotlin merged kotlin-stdlib-jdk7 and kotlin-stdlib-jdk8 to kotlin-stdlib.

Refer to https://kotlinlang.org/docs/whatsnew18.html#updated-jvm-compilation-target

The screen shot like below:

Currently, when try spring-boot 3.1-M1 with starter, still using kotlin-stdlib-jdk8:

[wilkinsona]

Thanks for the suggestion. For Gradle projects, we plan to remove the dependency entirely as Kotlin's plugin adds it automatically (see spring-io/initializr#1376). We should still do something for Maven though.

[wilkinsona]

Closing in favor of spring-io/initializr#1386.